My name is Laurie Chris I want to welcome
everybody to our first program for

this spring two thousand and

thirteen semester in our series
splendid research at the library.

Manipulating light from designed
to application is the ninth panel

in the blended research series and
it's sponsored this time by the factory

engagement Department of the Georgia Tech
library as always but also by

the young professionals group here at
Georgia Tech and Stephen I see you here.

Steven leads that group.

Blended research at the library is
a panel discussion series focusing on

multi-disciplinary research at every
session we try to have faculty postdocs

and research scientists and Georgia Tech
graduate students from various departments

across campus and talking about
an area that crosses disciplines.

Today each of our panelists is going to
give a brief presentation on their topic

and then we're going to follow this
up by a question answer period and

hopefully some discussion.

Our first speaker is going to be Jennifer
Curtis Jennifer is an assistant professor

in the School of Physics and

she's been with us here at Georgia Tech
since two thousand and seven.

Jennifer received her be a in
physics from Columbia University and

a Ph D.
in physics from the University of Chicago.

She also spent a great deal of time
at the University of Heidelberg and

that included a very prestigious
Humboldt fellowship is there.

Her current research interests include
cell mechanics molecular biophysics

bio nanotechnology and
optical manipulation.

Our second speaker will be Joel Hale
us and Joel is the principal research

scientist at the Perry research group in
the school of chemistry and biochemistry

he received his bachelor's of science and
physics from Georgia Tech and his Ph D.

in optics from the University of Central
Florida his current research involves the.

Characterization and implementation
of organic materials with large

ultrafast nonlinearities for
photonic applications.

And then our last speaker
will be connect for

when taste Hernandez who is a senior
research scientist with the Copeland

research group in the school of
Electrical and Computer Engineering.

He received his B.S. in physics from
the National University of Mexico and

his Ph D. in optical sciences
from the University of Arizona.

His current research is focused on
investigating the device physics and

device engineering of a wide range of thin
film devices as well as the optical and

electrical properties of the materials
used for its realisation.

I also want to thank him very much for
a last minute stand and

some of you may have noticed a different
name on the list if you noticed.

James and they work in the same group but

James had a family emergency and
was not able to be here.

So with less than a week's notice we
definitely appreciate him standing in

without our old Welcome Jennifer.

All right so

this is a really interesting
forum here I think this is great.

I'm curious to see how things go.

So I'm going to have to work hard not
to go more than twenty minutes and

when we do that is I'm not
really going to explain things.

I'm just going to tell you about things
that should get you excited about certain

kinds of things you can have a life and
then we can talk about it in the form.

OK So I'll start I'm going
to have a lot of movies.

OK to keep people awake so
what you're looking at are multiple

diffraction limited focus in
a microscope that I'm imaging and

moving around as I'd like to in real time.

OK And what I'd like you to
do is at the end of this talk

understand why I'm interested in
steering light into three dimensions and

what applications can come from it.

So that's what we're going.

Why.
And also a little bit of how we do that.

So the two applications that
I want to tell you about.

Our applications where
we use a sort of that

we use a technique called
optical tweezers or

optical traps which are used to do all
kinds of fascinating things including

probe molecules and cells and I'll tell
you a little bit about what they are and

how we do that and
then I'll tell you about

a new direction that I'm moving into which
is patterning light to stimulate cells.

Really I'm just on the patterning
right side that's my expertise but

the things that you can do or
neuro science are fascinating and

I think they're worth
bringing to your attention.

So what is an optical tweets are OK It
sounds like what you might think if I

had a should bring a pair of tweezers here
and I wanted to pluck my eyebrows right.

And somehow shaped my eyebrows.

I would have control to manipulate the
hair in my eyebrows and optical Tweezer is

exactly the same thing except that it uses
light to manipulate microscopic matter.

OK.

The real name is the optical
gradient trap or

the optical trap that goes by
different names and what's so

exciting about the optical trap
is that it's pretty easy to bake.

OK.

Basically what you need is a laser beam
just a little bit stronger than this just

a few milliwatts OK And then what you
need to do is bring it to a tight focus

as tight as you possibly can and
then in that tight focus objects become

if they have the right index of refraction
compared to the surrounding medium

optical forces lead to them becoming
trapped in the in the almost in the center

of the focus and here is where I'm going
to start going blending over the details.

OK Now what's interesting about it makes
it a useful tool is that it's possible to

couple it into a microscope and in fact
use the same objective lens that you would

have on a microscope for imaging sells for
imaging whatever it is that you're doing.

If you're working in material science
call it science whatever you want

you can use the same objective lens to
take a collimated laser beam bring it

to this type focus create the optical trap
and then simultaneously use it to image.

What stuck or goes into that trap.

OK Now these are.

Kinds of things that we can do in
that in fact we do in our lives but

with the shows up.

There's a couple of cells.

On the surface here and this is
a microspheres about three microns inside

and it's been held in an optical trap
right now it's kept it's been for

it's held in the trap and
it's believed that the stage is moving so

that the bead is being carried away
from the cell so you see that I

can manipulate an object and move it
around with respect to the silence.

Now it just so happens it's tother to the
cell by some material on the surface of

the cell and so when I bring
it too far away from the cell.

I lose a battle of tug of war and
the the fly backwards.

OK So manipulation is something
that you can do with optical traps.

You can also manipulate individual
cells and for the sake of time I think

I'm in a I'm going to skip this movie
with you can ask me to show you later.

But these are two dividing cells
are not bound to the surface.

I can use light to grab on to one of these
cells and does that grab the two cells and

displace them around or grab the beads
that are also attached to the cells and

displace them around.

So you can manipulate so there's
there's it's sort of interesting for

just moving and
sorting objects if you like.

Now the other thing you can do with
an optical trap that turns out

to be one of the favorite things that
biological physicists like to do

is you can measure forces.

OK And the basic idea for

measuring the force is to be right
in the center of the big Ok then

there's basically an average of zero
four solid place from the BE restoring

force on it due to the gradient forces
in the optical drive light the middle.

OK And if it's this way and

that's how they saw different place that's
an indication that there's some force.

Now if you're looking at
this from the top down.

Look at the position of the B.
with respect to the center of the trap and

that's calibrated back at least in
the springs that this is a track and

you do that you can estimate with
the forces on the field you can do this

really well and the kinds of forces that
we can measure are on the Pico Newton

scale which is basically the order of men.

The gravitational force between me and
her.

So it's tiny.

But those kinds of forces really
matter when you're dealing

with biological systems and
when you're dealing with molecules.

OK So one of the things that we do with
an optical trap and allow is we probe

something called the parasailing matrix
parasail a matrix is also sometimes goes

by the name like OK Alex I'm not going
to get into into too many details but

basically this is a cell here down to the
surface of the cell is a thick polymer me

tricks which is very difficult to
visualize which typically is visualized by

biologists who add particles around it
to see where the particles don't go.

And so the thing that we study is
exactly what took place right here.

OK And it's interesting because this
polymer matrix is correlated in its shape

and its thickness and its contents
with processes that involve sell it.

He which includes So
migration cancer metastasis but

little is known sort of about the
mechanical properties of this matrix its

spatial organization or how in the world.

It happens to mediate those processes.

So what we do is we take one of our
calibrated optical traps and we push it

into this parasail you a matrix and we're
sort of like feeling with our eyes closed

to see if we can somehow he's forced
Herb's that we measure when we're pushing

into it to back out structural mechanical
information about the cell code.

So we have more understanding about how
it's used by the cells to achieve those

different processes so I'm not going
to tell you how what that exactly what

the data is but I'll tell you a few
punchlines So one thing we found is

that for the cells that we're looking at
the cell code is forty percent longer or

wider away from the surface than what you
would find from the standard techniques

which are these crude techniques where
people are actually adding fixed red blood

cells believe it or not to the solution to
see it the other thing we found is that

the force curves indicate that there's
a two layer structure in the cell code of

the cells that we look at so
you get structural information and

then another thing which is quite
difficult for me to explain how we got to

this one prediction that we have from
our optical tweezer experiments is.

The cellco should act as a seed that is
that this matrix has a spatially varying

mesh eyes as you get further and
further from the cell.

So that smaller particles should be able
to penetrate further than larger particles

and we tested that which is
easier to show you right.

Once you have a prediction you can test it
and what we did was we sprinkled particles

of different sizes into the cell code and
we looked at the average.

This is that they were able to make the
cell surface where the concentration is

constant and so these are two micron beads
that you're looking at here for you and

you'll be telling all of the self-service
this is intensity of this for us and

beauty versus out one hundred
meter B.'s plateaued a distance at

three microns three hundred meter beats
five to five microns and so forth and

so you can get from you.

Besides if you want think of it
this way mash size versus OK so

this here is from our local and

user these particles which
announces that I'm showing you.

So those are the kinds of games that
you can play all right now I'm going to

tell you about work that is not from
my lab just for completeness and

because I think this gets people excited.

OK so simple molecule manipulation and
measurements

is something that you can do with tweezers
and it's just absolutely beautiful work.

What you're looking at
here a couple of cells.

Whose side of skeletal network has been
labelled with a fluorescent dye in

particular the yellow filaments that
you're looking at here microtubules and

among many things they're responsible for
they sort of act like a complicated

highway for the cells in which there's
trafficking going on in transport of

molecules from one side of
the cell to the other and

that's all driven by molecular Motors in
particular one molecule that walks along

these microtubule tracks is called the
Neeson and it basically carries cargoes

that's of course little sort of limpid
by a layer Spears above its head and

then walk alone from one side to
the other the cell or however they go OK.

And so it's something like someone
carrying cargo on their head and

there's been beautiful work where
people have sort of done things that

you couldn't imagine so you can't cram
onto a tiny molecule with an optical trap.

Not that thermal diffusion would when
there's not enough to grab onto there's

not enough force.

OK but what you can do is
if you know the chemistry.

You can connect a handle to the molecule
that you would like to study like one of

these microspheres that I play around with
all the time you connect it and you try to

make sure that you don't hurt the molecule
in that you have a single molecule and

then you can use the too easy decision.

And the molecule on the track my
OK I'll say this solves them that

all of this is so somehow molecular
biologists made this for you and that way

you can do it you can hold on to the beat
put a T.V. in the system like a motor.

Well OK and

you can play games with that like how much
force can I exert on it so that it starts.

That's what the that you're pulling
back on the fight against right.

How much D.T.P.
does it need to take a single step.

OK what's a chemical mechanical coupling.

And so forth and again for the sake
of time I want to show you this but

there on You Tube and there's a link
here this will be posted online.

There's beautiful movies that show what
people have learned from these kinds of

studies and
if you just go into the literature

folks have been able to show that these
molecules make steps of one step.

That's only meters long for
each and each world.

You know when all of that was
done with a single optical track.

You can also look at the distribution of
step sizes that's what the sister gram is

you can look at the speed that
one of these translates along

a filament as a function of the A.T.P.
and so forth.

So that's one optical track.

You can do pretty neat things I hope you
agree there's lots more that folks have

done and then you can start to say well
what would you do with more right.

And these are a list of things that

you can do down here folks have taken red
blood cells attached to beads to them and

stretch them to measure the mechanical
properties people have shown that

mechanical properties of red blood
cells very different diseases and

this is relevant to how the blood cells go
through your capillaries you can measure

membrane tension in the membrane reservoir
in the cell and look at conservation.

We've looked at sort of artificial
biomimetic side the skeleton networks and

how those link up by holding
building basically building them.

All right so
there's an interesting reason for

wanting to do this on the other hand
in the process of learning how to make

many many many many optical traps which is
really what I did in my graduate studies.

It turns out that that application.

If you want to think of it this way
can be extended to a new field which I

think is incredible and it's a field of
after genetics and the basic principle and

up to genetics is that you
can genetically engineer

cells to express specific proteins
which are gated to respond to light.

OK So that means of those proteins aren't
doing anything until you put a light of

some shining light on it and
then suddenly they become active and

I've seen at the last meeting that
I've been to recently they're

they're starting to do this to so
many different components in the cell.

It's incredible what you can do and it's
incredible that you can sort of look at

the molecular machinery bit by bit by bit
and say Now it happens if I turn this on.

Now what happens if I turn this on and
so forth.

Of course you have to be careful and

make sure that what you're doing is
still biological but it's fascinating.

The control that you can have now the
thing that I find particularly interesting

is the possibility to modifying neurons

with a ion channel which is photosensitive
it doesn't have anything to do

with ion channels that are found
in the neurons in your brain.

OK it's a it's from algae.

But they can be that you can
convince cells in living

organisms like to see
profession to express.

These photosensitive ion channels and

when you shine a light on
a single neuron it will fire and

it will have the properties similar to
what it would if it was on its own.

OK now that's incredible.

OK because it gives you this this
distinct advantage into looking at

connectivity and.

Processing and
brains work in just culture and so

really what we're good at doing is
making spots in one dimension or

in two dimensions in three dimensions
putting where we are putting them where we

want to and then for these applications
to involve up to genetics.

We're looking more at how we can control
intensity where we have extended

illumination in two dimensions and
three dimensions and these things here.

You need the points.

Those are what you need for up to call
traps you need a diffraction limited spot

the tighter the better because the
stronger force now on the other hand for

these outer genetics
applications you can imagine

shining light on part of a neuron shining
light on three neurons and so forth.

So that's where we go.

So what's the trick for doing this.

I'll just give you a little
bit of the punch line.

But if you were making
an optical trap right.

What you want to do is take one and you
want to turn it into three for example and

put them in these three positions.

One way to do it is the hard core way
which is to split the single beam into

three being steer them with mirrors
into the back of the subjective lens and

have them end up where you want them.

OK Another way to do it is to do.

Timesharing and
deflect this being really rapidly and

have it be only in one spot at the time.

Another way to do it is to
put some kind of here so

that you met the interference
pattern of the three coming beans.

So that those who
are basically propagate as if

this these three incoming
beams that come in.

That's the trick that element is
called a defrocked about it and

the key to doing these different kinds
of illumination is knowing how to

design the diffracted optical element that
steers the light where you want it to go.

OK so how am I doing on time.

What time do I have.

It's going to think OK All right.

So really in order to do this you have
to know something about a laser beam and

basically there's two
important attributes.

There is the attitude and remember a laser
beam has a cross-section So this is

a spatial distribution of intensity of
the square root of intensity practically

OK And then there's the face and so
probably being poor in here these planes.

It has it has a spatially distributed and
it has some face.

OK And you can write it using scalar
field theory just to look like this.

The amplitude times to whatever that phase
is now it turns out the intensity that you

get in any of these things would
just be the would be square or

the amplitude squared.

OK and the game that we play for technical
reasons is to manipulate with this

phase so that we can get whatever
amplitude that we would like K.

now you can break this down into a pretty
simple problem and say well there's

two things that we really want to do with
single spots at least we like to position

beings in the X.Y. plane and one way we
know we can do that using optical elements

of these prisms you can take a beam and
you can bend it by using a prism.

OK And if you want to change
where something is an e

axial direction that is along the beam
you can put a lens and you can focus it.

OK.

And there's many different
ways to accomplish this.

But these two here basically amount
to changing the so-called way

friends of the BE OK and the way this
works if you think about both of them.

Those are optical elements
made out of glass.

They have a different index of refraction
of the surrounding air wherever you

are OK And so when you have a laser
beam which is basically has collimated

way friends and it passes through
something which has some top dog or

a few different thicknesses at a different
index of refraction as being tells it

all of the party says where there's
a gap in the glass the beam is traveling

slower but where it's been or the being X.
it sooner than it does words.

VICAR.

OK and
this causes shifts in the wave front and

you're basically writing onto
the wave front some new spatial face.

OK And so that's the idea.

So if you can figure out what phase
you'd like to have on your way from

in order to get the spots feel.

Intensity where you like
it you can go ahead and

design something like this to do it now
the key really is how do you do it.

You don't want to go and

start carving glass for
each into unique distribution you want.

I showed you that movie in the beginning
where I was rearranging many beans.

OK I needed to do that fast.

I needed it to be pretty arbitrary and
so forth.

Instead what we work with is
a defective optical element

which can mimic effectively
what you're doing here.

Mimic the face and in fact we use
something which is a computer addressable

defective optical element called
the spatial light modulator and

it's a lot like the liquid crystal
display that this projector is

using to make this image here.

So here's what it looks like and
you see this little screen right here.

I can expand a laser beam so
it's rising higher.

It's right here.

I can address each soul and
basically say Mr pixel you this Mr pixel

you that face and if I know what I want
the face to be I can make that beam split

into whatever number of beams I'd like and
have them position into three dimensions.

So the last thing that
you need to know to make

any sense of this right is some some
clue of how the algorithm works.

We work in sort of a special set
up where what we do is we have

the beam in the spatial light modulator
where we're going to write the face.

We have in the back focal
plane of the of a lens.

Typically the objective
whens that makes our traps.

OK.
And

there's a very sort of nice to call
pretty friendly mathematical relationship

between what you have here in the case and
what you have up here.

Basically the relationship between
the fields as a four year transform.

But that's nice because
you can say well out here.

I want five spots in these places.

I want this amplitude a prime.

What do I have to do over here if I want
to leave the amplitude fixed because

I don't want to waste my power.

But I can play with phase
as much as I like so

that I can get this
distribution over here.

And remember this phase doesn't matter.

OK that's the game that we play in
order to start making these patterns so

originally those always done for

me in the context of optical trapping
Here's a setup that we use laser

spatial light modulator basically a relay
telescope get it into the back microscope.

Here's part of the hologram we call
these space can of forms holograms

it's a bit of a misnomer.

And these beams that you're looking at
here are four hundred working optical

traps and this was a week of graduate
student work to fill two hundred of them

and if you think about how you
load them if you fill the outside.

You can't get anything on the inside.

So it's kind of like a computer game but
kind of stupid right.

So and then because it's computer
addressable you can start playing and

hoops that's not what I want
to hear is that the real one.

OK So these are three of
my chronic little spheres

each held by an individual optical trap
where each time you see one pattern.

There's a pause for
a moment where the the phase uniform on

that spatial light modulator is creating
that particular pattern the beat goes

into that pattern then it slightly
displaces and it goes to goes again.

OK All right so
here's the last two slides.

OK so I don't do this I collaborate with
people who do this in particular about

a million meet and again the name
of the game right is to take

tissue slices with neurons or
even living organisms like the zebra fish.

OK and to build a sophisticated
holographic microscopes which can

both identify neurons that you
would like to shine light on.

OK And then actually put that
spatial pattern of like there and

then some with teeny Asli readout
what happens as you're doing it so it

really we talk about this being introduced
this really is something that requires.

A special team of people I don't think
it's it requires a lot of knowledge and

so these are the kinds of things we go
through identify what region we want

to stimulate Is it one cell is it one
point on a cell is it the entire cell.

There's a cell here in this case down.

You know only wanted to eliminate the X.

out of it you calculate the face
hologram to get that pattern of light

you shine it in OK and then you measure
that's that's the name of the game.

Now what really sort of shocked me in his
sort of forced me to confront some ethical

questions because I've never worked with
animals before is that there's already

a very strong area of.

Basically opt of genetics where people are
just shining light on a cluster of neurons

that's not so specific and
delicate in the way that we can do it but

they can already control behavior so

you see this mouse he has a fiber
optic cable coupled to his head.

Here's an example of what
you can do with this.

So this is let's see if we can play it.

Here's a mouse like that who has a private
optic cable coupled to his head.

OK And when you see it glow it
causes him to run their clothes and

he starts running.

OK so by accessing the more the motor
cortex of this mouse his brain and

shining light into it because the mouse
has been genetically modified

to have these light sensitive ion
channels you can control his behavior.

It's creepy.

OK it's creepy but
it's also really fascinating and

so I think that leaves us a lot
to discuss and I'll stop there.

Just so.

Thank you.

So we can suppose this one works OK great.

Glad everybody's got snacks now.

OK So while I'll be talking

probably a little bit more on the physics
side although we are a chemistry group and

I'll be doing this a little bit
different than Jennifer and

that probably the stuff
that we do in our group.

I'm only going to be talking
about at the very end.

I found out as I was making this
presentation that it helps to kind of

frame the whole picture.

And so I want to kind of do
that during this talk and

so information's a pretty generic.

Term but what we're going to be
talking about today is the need for

developing I guess better methods
of transferring information.

So I think probably most people
are familiar with the type of digital

information that is required for
what should be entertainment.

So in that you can see that you
know between streaming audio or

streaming video or
any type of thing including online gaming

there's a lot of data that
needs to be transferred

not only in the audio not only for
audio but for video as well but

entertainment is really not the only
region over which intensive information

transfer is necessary data gathering and
I say that as a general term.

When you have are if I D. tags that
are tagging multiple shipments and

you want to track them as they're going
through you know they're very shipping

locations if you want to look
at global weather patterns and

try to be able to simulate them.

If you want to try and
model market dynamics.

There's a lot of information that
actually needs to be acquired.

And then there's the whole thing
of what's called Tele Presence So

a lot of folks have probably
done telecommunication

telecoms rather where you're doing
both audio and visual interaction

telepresence is more about accentuating
that kind of environment so

that you can actually interact with
the other the other person and

so you can imagine that being the case for
remote learning.

If you're trying to teach classes
to a developing nation or

if you're trying to do tell us your
jury and this is been around for

about ten years now where a surgeon can
actually be able to manipulate robotic

arms in a remote location to be able
to do surgery that he can't access and

so anyway there's a wide variety
of reasons why we need additional

additional means to be
able to create better.

Information transfer.

And I took this from the I.T.
you that monitors information

transfer on the Internet and you guys have
probably seen a table like this before.

Which kind of gives you an idea of how
long it takes to download something

whether or not it's just a standard D.V.D.
movie or a video clip from You Tube or

something like that particularly what you
get to your house if you have Comcast or

universe or

something like that it's probably
about twenty make of it's per second.

So this is actually
a little bit faster and

we don't even have a line
here that talks about H.D.

video or Blu rays and and how long it
could potentially take to download that.

And you know not surprisingly
there's many many more people about

a third of the people on the planet
Earth are actually online.

There's increased ban with
the increase almost about by

a factor of ten over the past five
years and you have both mobile and

wired broadband that's growing so.

I think you can get an idea that in the
future we're going to need better means

to be able to.

To increase data transfer the question
is what what is necessary to do that and

there are three basic things that you need
to understand one is the generation of

that data on one end so whether that's you
know in the cloud somewhere at some server

farm and being able to actually generate
those data in an actual processing

form to be able to transmit that from that
server farm down to wherever it's going.

Whether it's going to an office or
to your home or somewhere else and

then being able to process it meaning.

How can you route that information so
that goes to the proper place and

for me the best way to think about that is
to think about that in terms of traffic.

It's a really good analogy.

And so I hope this is no one's address
because I just pulled this off the web so

I have knowledge as if
it is your words but

if you're trying to get to
work in the morning and

you're living in Dunwoody and you're
trying to come down to Georgia Tech.

You probably have a route that you take.

And when you start out you
start out in the neighborhood.

And you probably have two lane
road there's not a lot of traffic.

There's not a lot of cars going over there
as you get on to Ashford Dunwoody it's

a little bit broader maybe there's like
a four lane road and you have to come into

contact with intersections that
are controlled by traffic lights finally

you're going to make your way over to a
junction where you get on to four hundred

which is a rather large highway become
pretty crowded and then you're going to go

to the downtown connecter where you have
basically a sixteen lane highway and

so the infrastructure is in place for
you to accommodate

you know many people as necessary as
you get closer to the heart of town.

There are many more lanes to a comedy many
more travelers in the infrastructures in

place to be able to get you from basically
one connection point to the other

in a sense it's routing and

so the infrastructure is already in place
that doesn't mean that it can't be better.

That doesn't mean that certain roads don't
need to be widened it doesn't mean that

you you shouldn't have smarter traffic
lights that sense traffic patterns and

can be able to make it a little bit easier
for you to get to work in the morning in

this analogy is is pretty much identical
to what goes on in terms of data transfer.

So I don't fully understand this entire
you know this entire diagram here but

I think the point is that you have
the initiation of data someplace like

a data center a server farm and
it's going to travel along its highway

to a place where it needs to be
routed into needs to be routed to

the appropriate location whether it's
to you or it's to somebody else.

And there are a variety of different
locations where it can potentially end up.

And the whole idea for

data transfer is to be able to make
this a faster process and again.

Traffic is going to become greater
You need to be able to make sure that

the infrastructure can be adaptable moved

quicker it can accommodate more
people more lanes on the highway.

And so.

Onyx has been doing yeoman's work over the
past hundred years working with coaxial

cables and other types of cables to be
able to facilitate this data transfer so

photonics which includes Not surprisingly
the generation transmission and

processing of light has made inroads but
it's mainly been in about

the past thirty years and I would say it's
primarily in the transmission of data and

we'll talk a little bit about
that here in a second but.

I want to discuss the idea of bandwidth
because it's kind of a nebulous term but

the way I like to understand it is I
think everybody understands audio signals

voice signals so
typically your human ear a can

can hear anything from about twenty
hertz up to about twenty kilohertz.

So that means if you want to faithfully
transmit that data you need to

have about twenty kilohertz a band was so
that you don't cut off the high notes and

you know cut off the low notes and

it turns out that not surprisingly video
requires more bandwidth than audio quite

a bit more isn't as it turns out and
digital video requires more than that.

Obviously H.D.
video would require even more than that.

So what's the point there.

The point is that typical T.V.
let's say a cable station or something

like that operates in the frequency
ranges that range from a few hundred

megahertz to up to a few gigahertz so
you can imagine if your channel needs to

support say ten megahertz there's only so
many channels that can fit in that band.

So there's only so

many if you want passengers that
can travel on that highway.

Now if you move up into
the optical domain.

You're talking about increases in at
least six orders of magnitude in terms of

frequency there is a much larger frequent
scene window which means you can put a lot

more data you can put a lot
more channels there and

that's the benefit of optics that's
one of the benefits probably

the one that most people are familiar with
it's the capacity for caring information.

It's much greater.

And then for electronics.

There are other potential benefits.

You don't have electromagnetic
interference or

you have very little compared to when you
have electrons transferring information.

It's relatively low loss and

part of the reason that's beneficial is
that most of what you'll see the photonics

is good as transferring information
over long distances and so

you want to make sure that you aren't very
lossy over that distance otherwise you're

going to have to regenerate your signal
and that's going to cost power and time.

And the other thing that is that it's fast
and when I say fast I don't mean that

actual transfer of information because
electronics transfer information

pretty well in fact on the order
of the speed of light.

So you don't get much benefit there but

when you're trying to process data when
you're trying to route it from one place

to another that's where
the benefit actually really lies.

So there are a lot of drawbacks and not
surprisingly the biggest of which is cost.

So for instance for
fibers which transmit data via light.

It's a lot easier to use what's already
in place which is copper that transmits

electronics electronic signals that
doesn't mean that people don't have fiber

going in close proximity to their home but
it's in all likelihood they don't have

fiber coming right up to their home may
have fiber coming to their neighborhood

and then it may get converted in
electrical signals and sent to your home.

But right now it's a little
big Spencer to come up and

dig up in your yard rip
out that co-ax cable and

throw down knuckle fiber and the other
thing is from a processing standpoint

is that electronics are just more
mature and so there's just a lot.

There are a lot more ways for
them to be able to route information.

I would say efficiently than optics.

But hopefully that's changing.

And so

I would say the biggest breakthrough in
terms of using photonics to be able to.

Be involved in this you know information
transfer is the introduction of fibers and

in fact I think the Nobel Prize in Physics
A few years ago was actually given for

the you know basically the inception and

the understanding of how to use optical
fibers to transmit information.

So if you're not familiar
with an optical fiber.

It's basically a glass.

If you want a very very thin
glass rod encapsulated by

probably another piece of glass
that's of a slightly lower index and

what it does is allows light to basically
bounce back and forth inside here.

It reflects off the surface here.

And if you design the glass well which is
already pretty transparent so you can see

these are the wavelengths that we're going
to be operating at this is called the near

infrared It's right outside the visible
part of the electromagnetic spectrum.

It's pretty low in and
of itself using silica or glass but

you can make modifications to
make it even you know less lossy

which means you can transmit data even
further without having to regenerate it.

And so I think those are the two
key breakthroughs that enabled

people to start using fibers to
be able to transmit information.

It's that you could develop
low last five or so

that you can transmit this information
over long distances and and

then they were actually
able to develop amplifiers.

So once you're once your signal
the case pretty you know pretty well

to the point where you're probably
going to get a pretty bad signal

you want to be able to amplify it.

Well before what they had to do is they
had to convert that optical information

to electrical information amplify it then
convert it back to optical information

then go on its merry way.

Well they figured out ways
to be able to do this.

Optically so
that you didn't have that interruption.

And so on the transmission
side this very important and

although I won't talk about it much today.

The fact that you could actually take this
laser and so this is an example of a laser

actually propagating light through
a fiber or at least the glass rod here.

You could actually embed in from made.

On that laser so that was your way
of generating the actual signal and

you would propagate along its fiber and
it would go on its merry way.

So.

I think where optics lags behind
electronics is in the process

in department meaning if you're trying to
you know if you have a bunch of signals on

your optical fiber and it gets to this
decision point it needs to make a decision

of how to go either to a home or
apartment complex or somewhere else.

Typically what is done in this is actually
shown here is if you have a bunch of

different signals and you want to go
from this channel to this channel.

You need to be able to do
something to switch it.

So typically what's done is OIO and

this is what we just talked about
it's going from optical to electronic

to optical meaning you have your signal
coming in has to be converted to

all electronic signal before it's rerouted
and then converted back to optical.

So this obviously takes advantage of
electronics it's much more mature but

the switching time isn't particularly
fast and there's power consumption I mean

you're converting data from one
form to another and back to it.

So if you could avoid that all the better.

What people have been doing more recently
and they kind of term it all optical

switching but it's not really is is taking
something where you actually don't convert

it to electrical signals but what you do
is you take this input light signal and

you bounce it off a digital light
processor so this is a bunch of

micro mirrors little tiny micro
mirrors that you would see in a deal.

P. television and and you can basically
control these mirrors such that they read

direct light to the appropriate fiber so
that it goes on its merry way.

So the thing is this isn't really all
optical right because you're doing you're

sending electronic signals to move a
mechanical mirror so that you can do that.

However you're not having to convert
to a what electronic signal so

there is a benefit but
the switching times a very slow and

this is a relatively large footprint.

Now you know if you're if you're sitting
you know in a in a township and you've

got this big old box and you're trying to
you're redirect you know a lot you know

a thousand data signals to a bunch of
different locations you're probably OK but

think of if you're in a you know it in
a server station were a bunch of different

servers and there are a bunch of different
users that have their data on their

individual servers and you're trying to
access that individual person's data.

You probably want this device
to be much smaller and so

what we're trying to look at here is
whether or not we can use optics to be

able to do switching all optical
switching real optical switching.

In Unfortunately you need to go to
a region where you're not operating

linearly anymore.

But you're using nonlinear optics and
I won't get too much into this but

I think most people know that if
you shine and and an optical field

onto a medium what what happens is you're
able to actually cause the electron

clouds in those in that media to oscillate
you're creating an induced dipole And so

what happens is when you're on when you
have very very low light intensities

infectiously shown here in this
little squiggly line right here.

If you have a very long week optical field
what happens is your induced dipole moment

scales literally so if you double
the size of your optical field you double

the size of your induced dipole moment.

However if you go to really
strong optical fields.

What happens is this doesn't this little
transfer function doesn't behave you

linearly anymore so what you get out
here is some kind of perturbed wave.

You know wave here in this perturbed
wave is actually indicative of

the fact that you change the optical
properties of the material.

So with very intense light you can change
the optical properties the material.

So some optical properties
are probably familiar with or

the refractive index is responsible for
a fraction and

a fraction dispersion and
absorption which is responsible for

absorption and it turns out for nonlinear
optical materials you can actually modify.

These material properties and
they're basically going to be pretty

proportional to the amount of light that
you actually hit the material with so

you can control the amount that you're
changing those optical properties.

So why is that important.

Well normally Photons don't
interact with one another.

They're very they're very stubborn about
that they have very little interaction.

However if you can actually modify
the optical properties of material you can

actually cause light to redirect light and
that's actually shown here is that if you

have a very weak signal and it tends to go
through this arm and normally if nothing

else happens it's just going to pass right
through here and go on its merry way.

But here.
If you send in very intense pulses what

you can do so you can actually modify
the optical properties the medium.

And you can actually control whether or

not certain signals actually pass
through this switching device.

And that's what we're trying to do
here we're trying to use light to

control light.

This is this is all optical signal
processing this is where we're trying

to make inroads.

And finally we're getting more
to the material section but

what I wanted to point out here is that
people have been doing all optical

switching with inorganic materials for
a little while.

Probably more than a decade now they've
been using our old buddy the fiber.

And it turns out the optical
fiber is pretty good.

It's a mature technology get
really fast switching but

it's non-linear response or
it's non-linearity isn't so big.

So in order to be able to take
advantage of this you actually have to

make relatively large devices the amount
of fiber that you have to use is actually

pretty large and if you're not constrained
in terms of space that's probably OK.

People also use semiconductors silicon for
instance and silicon has the benefit

that actually both of these technologies
have the benefit they they not only guide

light themselves but they work as
the actual medium that does the switching.

So you can imagine that
if you have like a long.

Strip of silicon in here and you can
actually propagate light through it.

What turns out is that you can
confine that optical optical mode very

strongly in fact probably about on the
order of at least an order of magnitude

stronger than you can in in a fiber and so

the benefit is that your non-linear
response grows tremendously.

So people have been able to use this
to be yet able to send in signals and

then be able to switch them
out at different ports.

So it has a lot of benefits it's
clearly into global because

everything is based on silicon just about.

So that's not an issue.

There's very strong confinement of life.

However the amount of Taylor ability
of your material is pretty low and

the switching response
times can be impacted.

And so what we wanted to do is
be able to use organic materials

to be able to try and solve some of
the issues that have come up here and

don't be bothered that you
can't read this I can't either.

But the point was to show that it least
through using organic materials and

particularly molecular engineering you
have a lot of different avenues to be able

to modify the materials properties that
you don't necessarily have when you're

using semiconductors or fibers and that
means that you can potentially change or

modify their nonlinear optical properties.

You can also change their physical
properties which is going to be important

because you want to be able to make sure
they're stable you want to be able to

integrate them with other devices so there
are things that you can do to be able to

modify these properties one
particular set of materials

that we've been really interested in our
group have been pulling meat molecules.

So you can see that this is basically got
a conjugated bridge here and what it turns

out is pulling meat lines behave an awful
lot like molecular wires and what I mean

when I say that is that the electrons
along this bridge are highly polarized

meaning the light field the optical field
can interact with them very fission.

And it can drive them very easily.

Consequently.

They have potential for
having very high non-linear response.

What the other thing that's
interesting is just by simply

modifying the length of this
molecular wire you can dramatically

alter the linear non-linear
optical properties.

This is kind of shown here.

Most people know what a bandgap Is it
turns out these organics have something

like a band gap as well and simply by
controlling the length of this molecule

you can make you can modify the that that
linear optical property dramatically.

And it turns out.

Consequently you can actually modify the
non-linearity quite dramatically as well.

In fact the non-linearity isn't
proportional to the length that you

change this but it's proportional to the
link to the power of like seven to eleven.

So if you can make huge huge
impacts in terms of the non-linear

response simply by modifying
the length of that chain.

So hopefully that's at least given you
a precursor that this could be used for

all optical switching and so
what does all optical switching or

most of the time we use what's called
the nonlinear for active index.

This is what allows us to do
that all optical switching.

There is a non-linear absorption
coefficient which is valuable for

a bunch of different
applications as well and

including my cross to be in some other
things for all optical switching it's

something that we would really
rather not have to deal with.

So the idea is could we be able to use
these polling the time molecules to make

this non-linear absorption small but this
non-linear effect of the next large and

what's actually shown here is
the ratio between those two things and

it's shown for a couple or rather a few
different polling the thousands in

the only thing that we've changed
is the actual molecular length.

But you can see we've made very very
large swings in this response and

more to the point if you want to operate
in the region that's appropriate for

telecommunications.

We can modify that molecular property so
that it's appropriate for that.

So so that sounds all well and good.

We've been able to make molecules that
have very good non-linear optical

properties the problem is when
you're dealing with devices.

You're not working in
the microscopic regime.

You're working in the macroscopic regime
so you need to take a bunch of these

molecules and compact them in a very high
number density in a very small volume.

The problem is that when you do
that with these poly meet tons.

They don't behave the same way.

So you can see in a dilute
solution meaning these

molecules don't really interact
with one another at all

they have this absorption spectrum
that looks really really sharp.

It's pretty indicative of what
a poly meet one should look like or

if we start putting like ten percent of
the dye in a particular host and start

increasing that volume fraction things
behave much more poorly you start getting

losses out where you don't want losses you
start modifying the non-linear response.

So what we need to be able to do is
figure out whether we could modify

the molecular properties to
be able to positively impact

those properties in the solid state
although you probably can't see much of

a difference between these
different molecules here.

I think you could probably agree
this looks a little hazier

than these other films.

So these are films number density
films made out of this and

if you look under microscopic images you
can see things don't look so good when you

look at this particular material but
if you can modify that molecular response.

You can actually make it so that these
materials actually behave much more like

they do in solid state as they do and
in dilute solution.

And so this is effectively what we've
been trying to get at was taking

things that we know have good microscopic
Dr optical properties and moving

them in a macroscopic domain but the
question is can we do anything with them.

Well you could use organics to be able to

not only not only try
out you know help help.

Transmit light but

also to do the all optical switching
much like you do is silicon.

However why not take advantage of
what silicon offers you which is

very small confinement and
technology that already exists and

that's what we're going to do instead of
having a silicon that just has a basically

a strip all the way around it where if
you remember before the optical field

was pretty much confined within
the silicon if we split that in half.

We can make sure that the optical field is
combined in this gap in between there and

now if we can put our nonlinear optical
material in that gap then we not

only have you know a waveguide that can
allow us to propagate light through it.

We have a material that we know has
a really good nonlinear optical properties

so are marrying the two.

This is called a silicon organic hybrid
device and we've been able to show that we

can do some all optical switching
type technologies with this material.

And that pretty much wraps it up but

what I wanted to point out is that for
our group and

our collaborators two is that we're really
working from all the way from fundamental

principles materials development to what
people like to refer to as primitive

components things that just on the verge
of being devices but not quite.

And we're trying to work with with
companies that work way over here that

really understand how that how to really
transfer information over a network and

we're trying to meet in the center and

trying to figure out what we
can do to help benefit them.

And that's that's hopefully what's
going to be on the horizon in the next.

You know four to five years
is what we're hoping and.

And so that's about it.

We have a lot of collaborators as you
can imagine because we pretty much

run the gamut from chemistry
physics to engineering and so

we collaborate with a lot of good people.

And thank you for your time.

Thank you.

All right.

So I'm going to follow also a similar
part to what Joel the basically provide

kind of a big picture of their area
that we are working in and then start to

some meaning to one of the particular
series of research in our group.

So that

I mention I'm going to be talking about
this big picture and the specific

devices that I'm going to be focusing
at the end is organic solar cells.

Hopefully you will see why.

So to me when I have
actually made my Ph D.

in optics in non-linear optics so
similar to things like what the Joyal

talk about but
to me something that really motivated

me into going into print electronics
was the savior of been able

to print circuits brains D.B.'s
print computers right on on paper.

And when when you started
looking at the story of

of these I mean it's all
about communication right.

Sharing information sharing ideas and

this has basically revolutionized
the human history.

Since good timber with the industrial
revolution the kind of the steam

power press where you could now
print hundreds of books per hour

to the twentieth century industrial press
where you can print probably thousands.

I mean it right.

So this need for sharing information and
processing information.

Obviously the House also
been the Belak independently

in a few of their areas that.

Towards the end of the century
are meeting finally together.

So one of these areas is computing right
so where we are taking electricity and

we are producing logical
very medical creations and

then we take these operations and put it
in electricity and basically display it or

use it in a useful way.

Optoelectronics which is just basically
devices that will convert to the city

to light and light to and electricity and
obviously the story of all these fields

are really quite old all
the way back from early in one

thousand sent three people were already
looking at ways in which we produce we

could produce live with electricity and
obviously in the last century.

There has been a great
explosion in terms of how much.

How many of our idea of
the vices that we have developed

to basically capture in machine.

For instance.

Absorb light and convert it into
electrical power and so on.

Finally the other kind
of area that is finally

coming together is telecommunications
such joy joy all mention

we have always had this need to
basically move information and

we have a ball in our understanding and
control of nature.

Basically we have moved from
transferring information transmitting

information with electricity to
use electromagnetic waves and

finally in in nowadays with light.

So.

What is happening basically
over the last thing

years right with the advent of
the smartphones and the tablet P.C.'s is

that people are really combining
all these these different.

Areas into single devices right.

You have to buy those
that can do computing.

You can capture images.

You can trust meet those images and
you can do all these great things but

what we're really trying to
do is to marry all these with

these super all the printing right.

So there is a reason why
we want to do that and

the main reason is that we want
information to be ubiquitous right.

We want to have information at the finger
of our troops wherever we are we

want to have access to all our
little gadgets and be everywhere.

So this is where science fiction basically
starts kind of approaching reality and

people have worked very hard for the last
twenty years to make this happen right.

And finally obviously the science
fiction community has

heavily profit on this great catch a year.

Finally For instance this year
something announce the first

transparent all the T.V. and
these T.V.'s are about a millimeter thick.

And they're completely transparent so
you can actually.

Picture that I venture you will be able
to really have this this type of deep

this place as an alligator company
in the U.K. call plastic and

Plastic Logic just announce
tablet P.C.'s Some

tablet in plastic that
very much look like this.

Like the newspaper seen Harry Potter
where you basically can watch a movie and

these are paper thin.

OK So among all this.

This is one we can use when I'm going
to be focusing on solar cells and

that's just because to me that's that's
an area that is very important because of

the societal need to a sickly overcome

carbon card.

Emissions right.

So in moving from the kind of
traditional devices like T.V.

star blitz to to this world for

flexible electronics we really need
a revolution in manufacturing.

That will allow us to print
basically electronic components from

transistors to light
emitting devices to power

devices the DECT or storage screens
everything we should be able to do that

we need to generate the knowledge to do
that on fully on the flexible substrate

of freeform substrates meaning that
you can print something on a glass or

on a bottle or
on the on your car directly right.

And there is established ways that
are being that have been borrowed from

basically the old printing community
right this roll to roll processes

and they certainly made
significant headway into actually

realizing this vision or the vision
that for instance you can take and

inject printer like the one
that you have at home.

Start the Bill of being simple.

For instance if you could
go to the Best Buy and

buy a key to print your cell phone or
some point.

So anyway.

The key components here is that we
should be able to print on flexible

substrate preferably on large areas right
we want to mass produce this thing we want

to get this in has many
surfaces as we can.

Your windows the roof of

of buildings and
we want to do that at a very low cost and

that's kind of the promise and that's kind
of the name of the game for the area.

So to realize this this vision.

What you really need to
do is you cannot do.

You cannot use this and bulky and brittle.

Silicon devices that are being used
right now to power our computers or

the smart phones and song.

We need to the relative Knology that will
basically be much more flexible literally.

Right.
That can be printed not in

very controlled environments.

Because these manufacturing processes you
want them to happen in air and not in a.

Super high quality clean room.

You want to therefore control all
the functionality send integrate all

these functionalities into devices that
are that had multiple layers that are and

where each layer has a few from few
nanometers to hundreds of nanometer OK

in our group we focus heavily our research
on Transistor solar cells and all that.

And that's those are kind of the three
main areas that we conduct research and

again I'm going to be talking about solar
cells but before I move into that I'll

like to just and this is again one of
those things that when you think about it.

This is actually fascinating at least if
it is to me when you think about what

an animator is right.

I don't know if everybody has a clear
idea of what an enemy Aries and

if you take a meter.

To be the distance between the moon and
the earth.

And then a meter will basically be
the size of the astronauts foot.

OK.

And something that is
really fascinating is that.

That size.

Actually if it is the size
of molecules that we

actually used to build these devices.

OK so the fullerene which is one of
the prototypical organic semiconductors.

The size of this molecule which
can test this sixty carbon

atoms will be actually
the size of a soccer ball.

OK So we are building devices
that contain literally

these are molecular devices that
contain on the rest to a valid.

And layers of molecules.

OK.

So matter of fact these devices are so
thin that their size or

the total thickness of the device actually
comparable to the weapon in the flight.

So hopefully everybody will be aware
that light is actually an extra money.

The weight.

So you have on a leg oscillation
the electric fear not elation the magnetic

field and
the distance between two peaks or

two ballots this is what
we call the web links.

So again just to give you
a idea of the size of things.

If you take the web link of red light.

OK And again using this analogy
then the Nano takes for

an oscillation of the electron electric or
magnetic field.

It's basically equivalent
in going from kind of.

Built of a football field to about
thirty yard of a second for book.

OK.

And actually in terms of distances.

OK the length which covers
from about three ninety.

Nanometers to about seven hundred
nanometers it's basically spans these very

short region of
the electromagnetic spectrum you

need to consider that we have microwaves
which are millimeter size and so on.

I mean radio waves and so we are talking
about really really really small scales.

So what happens at this is scales
is that light as we perceive it has

a very particular interactions that
actually when you think about we're

all very familiar with this interaction
the most important one has at least four

to be all devices is the fact
that two light waves interact

with each with which with each other
the interaction between these two waves.

You can think of throwing
to stones in a pond.

OK So
each stone is going to produce a ripple.

And when these two ripples meet if they.

Meet the crest going to be added
up if they meet out of Face

the water is going to stay still.

If they meet at the Valley that you are
going to have a slightly larger Valley.

So this is what we call
here not the interference.

OK And this is really what drives.

The research up to electronic
devices like the ones

that I just showed you is to control the
interference of light with these layers.

OK And
you are all familiar with interference so

this shouldn't be that the stench
of a concept actually we all

have play with soap and
water right and the bubbles.

Do you see all these color for
Patterson this actually interference of

light is the wide like going into the film
and it's interacting this way and

this interaction is going to make light
to be reflected at certain web links and

be transmitted and some other weapons and
this is yours for the Senate example right

where you have this film of sub water in
there and then if you pull feel to it.

You actually can see where all the callers
are interacting with each other.

So this is this is really what we want
one to control in Tintin the vices.

Now obviously there are the solar
effect that we are more familiar like

the light is reflected sure light
is just me that light is absorbed

light actually bends when you
tender some a Tiriel because

the velocity at which light
light's travel actually changes.

OK So if you're coming out of the last
at the end of a soul and when you enter

the street and you start to you cannot
travel as fast then the whole way for

naturally bends and
that's that's how dense this work right.

So all these effects.

We need to combine and

we signed devices that are actually going
to control these in the nanometer scale.

So this is what we do we kind of low.

Whatever devices we want to produce and
investigate.

Right.
We select the materials individually we

study the sport their properties so

we measure the refractive in this is we
measure electrical transmission and so on.

In some of these devices
specially solar cells.

It's possible for us to actually simulate
how light interact within the device and

we we can do simulations
we can do design and

then we finally fabricate devices right.

Analyze their performance and
we go back to the place to the beginning.

So.

As I told you I'm going
to be talking about for

the reminder of the talk
about solar cells and

that's just because obviously there
is there's a very big society.

On the other hand solar cell
it's an abundance of energy.

It's affordable reliable and
in principle it should be clean.

OK Now just to give you an idea of

the pool of energy that we

haue at our disposal is let me
show this graph where it basically

shows you the areas that you
will need to cover with solar

cells that produce that convert about
twenty percent of the energy that.

That gets to them into electricity.

To actually sustain the need for
electricity for the world.

OK.

So with their with their consumption
of three cities in three decades ago.

You will need an area when you add up all
the areas you will need an area like this

in two thousand and eight.

It's an area of more or
less the size of of Georgia.

OK to self and thirty's probably
more about the size of Texas.

OK And if we could basically build as many

solar cells as to cover that we will
basically solve the energy problem.

Now obviously there is.

Practical considerations that
doesn't allow us to do that and

the most cracked up information is cost.

It's really really expensive to actually
produce these current solar cells.

OK So this this table basically shows.

Their pollution of the efficiency of
the power conversion efficiency so

how many light.

How many photons you convert to
electrons right with these devices.

And show the steady increase with
the state of that solar cells are made

of silicon Crystal and
silicon putting out forty three percent.

They can convert forty three percent
of the of the incoming light into

electricity.

These are the types of cells that you can
put into a spacecraft because they are so

expensive but they are so I fission.

That you want to save real state and the
cost is this not the biggest driver but

these are not the type of that
you want to put in your in your

roof because it will cost you.

Millions of dollars to do that.

OK.

So people have been looking for
alternatives.

How to reduce the cost of this technology
and obviously waste increased the fish and

see right because the most of the more

efficiency we have we can reduce
actually the cost of of advices.

So what we do where we work
on organic solar cells and

these these these are one of the late
latest players in this game.

OK.

They were kind of our first
reporting in eighty six and

research really just started picking up at
about in the neuron the south thousand and

one but
they are also one of the fastest growing

technologies in terms of improvements
in efficiency so just last year.

Polymer solar cells and these polymer
sources just plastic solar cells.

They were reported to produce maximum
efficiency of about one percent.

This year.

Just last month and the which is a German
company reported twelve percent.

So we are now approaching a point
in terms of efficiency that

will make make it really
really competitive.

Now to give you a perspective more or
less what what kind of cost the solar

cell technology have so if you buy
a silicon Crystal in silicon solar panel.

OK you will need to pay in
the order of probably seventy seven

seventy cents for each What of electricity
that you generate with that panel.

With organics.

Current technology.

OK our current estimate because there is
really no commercial industry right now

but current estimates are that
the cost of electricity for

organic system there are there of
probably about two dollars per watt.

So what happened there.

There is a gap right a big gap
between the promise of using printer.

Print these printed metals and so on and.

To that I mean compared to the actual cost
that there is a big gap and the reason for

that is two things first of all
because the frequencies are much lower

the lifetimes are much lower.

Well also because some of the materials
that solar cells use are really expensive.

This is where we are in our group we have
been focusing our research on very very

quickly let me just explain to you how
a sorcerer works so our solar cells that

is basically a director of light that you
need to build to match the solar spectrum.

So in this graph it's shown
the solar spectrum right.

All these bands that you see all this
peaks are due to water absorption.

So these these these
are callers that are lost.

Once the song actually penetrates
to into the atmosphere and so

you really need to develop
materials that will absorb.

It's left.

Of the solar light when
it reaches the ground.

OK In total we have about

one hundred watts per square centimeters
that the power that reaches the ground

from the sun so we need to
convert that into electricity and

the way that that happens is that
photons are absorbed in a material and

that produces electrons and holes and
then you have something that is membrane.

OK.
That will separate these these electrons

electrons and holes and will prevent them
to reckon bine a lot of them into heat.

So the if if the scientists
membrane really really well

then you can actually split this holes and
electrons and

you will generate a current that
you can actually use this power.

So what we do in the lab is we actually
measure what it's called how much

the current the voltage
characteristics which is a measure of

how much power you can actually extract
for these from these devices and

that's basically kind of the area
below these these two curves.

OK that is enclosed with these
between these two curves.

So one of the primary focus of the
research that we have is that in common.

Solar cells you need at least
one transparent electrode and

then the other one needs to be
a mantle OK or can be metal.

That is made of a material that
is called Indian teen oxide and

that's really really expensive.

Most of the of the sources of
indium are actually in places that

are of high conflict on earth so
middle east China.

Places like that sort.

So we don't have any
control over the price.

So it's there is there's a great need
of replacing it with alternatives so

what we have been looking into.

Actually using polymers right
because polymers we can print

they are very flexible and
they are cheaper.

So here is an example of what we
this is one of the first successful

demonstrations are we having use.

Polymers polymers electrodes.

To actually build solar cell devices and
these devices are obviously not very

efficient but I mean it is starting to
do to be on the range of efficiencies

that we have about ten years ago with
materials that at maximum produce

around four five percent efficiency so
it's not it's not very bad a performance.

More recently we have managed in this is
structure we still have a layer that is

made of a metal oxide so our ceramic
material and we recently actually made

progress to actually replace that layer
with our fully poly American structure.

So this is your supply Asterix all are so

literally plastic solar cells
that solar cells we managed to

get the about three point three percent
which are actually quite comparable with

contour in that these are semi-transparent
quite comparable when you put a mirror

you actually get about three point
five three point six percent.

So it's not that it's not
a bad kind of efficiency

these have the advantage that they
are not using any expensive metals or

metal oxides so to increase the frequency
of cells one thing that you can do is

that with a single material you are able
to absorb only certain colors of light but

you can put two cells.

If you can make them semi-transparent
you can actually put oneself on top of

the other and

actually have sort of bigger portion
of the spectrum of the solar spectrum.

OK So this is what we have done.

And you need to engineer.

Again what I was telling you the electric
field distribution which is the that it by

the all these interference effects
that happen in these layers and

if you do that right.

You actually can model how much current
you can produce in these cells.

So this is just a plot that shows
how the current will bury If we bury

the weaknesses of the materials of
the active materials that we are using And

actually when when we go on fabric.

The basket we actually can
demonstrate our understanding and

simulations how recently.

So with current materials with
the state of the iron materials.

Actually this type of device is
now produced on the order of

ten point five eleven percent.

So these are the vices that.

In most of the structure is now polymer so

you can actually think that if we could
replace the stop electrode with with this

problem electrode which which is
something that we are working on

then we will have a really a structure
that potentially could be printed.

OK And finally in the last thing
that I would like to touch is

once you are talking
about clean energy right.

You really need to look at
the lifecycle of the technology.

It's not enough that you
say OK I can produce

this clean energy because I can
collect from the sun and so

it doesn't produce any emissions
a big question is what happens

with the solar cells after they die
right with the panels what happens with

the processes to produce these solar cells
which are sometimes very very dirty.

So something that we have been looking at
and this is where again we come full cycle

is to use cellulose which as we know
it's a very wet from from wood right.

So it turns out that if you
process this is sellers and

you're struck the main
components of cells are these

little tiny crystals that are called
nanocrystals of crystals.

OK so
they're about two hundred nanometer long.

And about twenty nanometer thick.

And if you produce them and

process them in the proper way you
actually can prove you actually can make

what will be the equivalent of
transparent paper like cell phone.

And there has been a lot of care for
of producing solar cells some paper but

unfortunately because paper
is very rough it's porous

efficiencies have been
really really limited mac.

On efficiencies on their own for
one percent.

So we finally this year just
where able to realize on these

noble substrate solar cells that actually
produce on there of two point seven

percent of our commercial
fishes is which is certainly

still a small it's missing because
again when we fabricate these cells on

glass we actually get under that of three
percent three point two percent and that's

because we are losing a lot of light
because now we have two metal electrodes.

There are probably one that you'll get
on while you were working on it and

we haven't addressed that problem.

We're not really to the point the relief
to these devices that actress killed but

we have been looking at it turns out
that things like we're getting these

are extremely sensitive now they're
not the tools that were working with.

Patients but we still have issues with

this relatively low temperature
hundred twenty degree C. Some of them.

Just don't like it and they are in
the process process very good counseling.

So what we've been doing lately
has been using I've been using

that as a very good guess as well but
the temperature's

So I would save it side
by side testing but

we've been able to trace the Life
least a few words to that story.

Probably not particularly
stable from the beginning but

we still have a little bit
further to heal in terms of

last fall for

him.

However with no.

So for
other applications can you somehow and

that's an interesting question for
a fraction.

I mean maybe if you had a series
of You could do certain

things but I've never really
thought that's a good question.

It does present something that I've
often wondered about which is sort of.

How much complexity code much later

information that you've ever

seen is pressed that limited
in the context of things I do

not question

the latest

we have the

right

thing.

Over blogger's So there

you are hard so

hard just fire so that you version of

what I heard just.

Fire now integrate with the ease

of your signal we're all what you are all

those years.

You're talking about very

worried about what your

life is

so if you're in the transmission route

it is a yes

that's a good.

Let me read your plan.

I mean like your area

right or

wrong road to get there is

so there is progress there.

So let me

play songs

from a very very

very slow

process where

Jim bursts out.

Mr Russell.

I know

there is a broad area where people

laugh but we also.

So

there's very very

question I have a question for
both of you.

The first is there is now or

in certain countries is there a focus
now on mostly fiber optics for

data transmission towers other places
where that or is it still too expensive.

I think that's a good question.

There are things that are more for
wireless technology

coverage as opposed to the transfer.

Long distances but
once there is that wireless technology.

You probably have better
coverage developing nations

than you do in the heartland
simply because from experience.

That's not so right.

And then my other question is interesting.

Now I with the sort of relatives squares
of the surface area you would need to meet

our total energy and if I understood
what you're showing me right.

That's direct conflict with everything
I've heard about solar energy which is

that there is no way even if you recover
the surface of the earth with solar

panels that you would be
able to get enough energy.

So I I don't know I'm
not an expert on earth.

So maybe it's the numbers
I've seen are like

taking into account the missions
is that your surface area.

This is like a person

or you I mean you cited
religious greatest right.

If you can solve the problem.

It's just really interesting because
it contradicts what I've heard and

it's interesting because I've often
thought OK you know we really have to buy

that we have to do something dramatic
because when you're winning wind energy

solar power and
these things are not sufficient.

So we really need to look elsewhere but I
think it's clear to those who are already

so you know why not.

Let's say I could magically
give you as many solar panels

that you want to raise
percentage you want.

Lol.

Maybe that's where the calculation.

Sure.

Want to clarify here a lot of stories

about it all are really

stuck with you.

I guess with the solar.

Like that.

So yeah that makes a lot less

place.

Yeah that's right.

You're always

very late.

I mean all right.

Because the lower floors

must drop the price

list price of solar power

Rose.

So there's really not.

Performance there sort
of which would be very

very busy life with the cost
of solar power it's much.

I think it's so cool.

It's so

when one less interesting thing for
people to hear about this.

I think this is cool.

There's apparently there's companies out
there now that you can basically allow

to install solar panels on your roof where
you don't pay anything and they just sort

of use it as a place to put them in your
promise or reduced rate for your energy.

So that's going to have a friend
who's doing this in Baltimore.

I'm not sure what the sun is like
there but you know it's good for

our people our.

There is

a lot of sort of feel for these people

I've.