1

Photonic Materials: Context, Principles, Selected

Applications

Professor Mark P. AndrewsDepartment of Chemistry

OutlinePart 1• Photonics – definition• Context – optical communications enablers: diffusion of photons into multiple disciplines• Background

– Basic E&M• Selected applications

– Guided waves– Devices and device constructs

Part 2• Selected Applications

– Guided Wave Raman– Nanoplasmonics– Chemical Solitonics– Lab-on-a-chip– Polaritonics– Photonic Crystals

Appendix• References

2

source: Photonics Spectra magazine

3

"Photonics is the technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. The science includes light emission, transmission, deflection, amplification and detection by optical components and instruments, lasers and other light sources, fibre optics, electro-optical instrumentation, related hardware and electronics, and sophisticated systems. The range of applications of photonics extends from energy generation to detection to communications and information processing.“

- The Photonics Dictionary, Laurin Publishing.

Photonic Context

Mapping how people use the WebBen Fry’s Organic Information Design

MIT

4

Glass Ceiling = 100 Terabits/sec

Electron = small range of frequencies Photon = BIG range of frequencies

World’s First Optical InternetCA*net 4

Calgary ReginaWinnipeg

OttawaMontreal

Toronto

Halifax

St. John’s

Fredericton

Charlottetown

ChicagoSeattleNew York

CANARIEGigaPOPORAN DWDMCarrier DWDM

Thunder Bay

CA*net 4 nodePossible future CA*net 4 node

Quebec

Windsor

Edmonton

Saskatoon

VictoriaVancouver

Boston

5

Photonics Enablers

1xNSwitch

CrossbarSwitch

VariableAttenuator

PowerSplitter

PowerTap

TunableCoupler

Multi/Demultiplexer

TunableFilter

Isolator Circulator PolarizationController

Modulator WavelengthConverter

TunableLaser

Amplifier Photodiode

source: DuPont

J.E. Midwinter, D. Marcuse, P.K. Tien

Straight Waveguide

E→

B→

k→

H→

μ

ε α

Ψ

P→

hν

π

ω

n ik+

χ

xioeI α−

Straight Waveguide

11 sinθn

6

Et

B

B

Bt

E

E

oo ∂∂

=×∇

=⋅∇∂∂

−=×∇

=⋅∇

εμ)4(

0)3(

)2(

0)1(

AAA 2)()( ∇−⋅∇∇=×∇×∇

gets us to

a wave e

quation

that links

electrici

ty, magne

tism

and light

7

Et

Btt

B

ofRHS

EEEE

ofLHS

tBE

oo 2

2

22

)(

)2(

)()(

)2(

)(

∂∂

−=×∇∂∂

−=⎟⎟⎠

⎞⎜⎜⎝

⎛∂∂

−×∇

∇−=∇−⋅∇∇=×∇×∇

⎟⎟⎠

⎞⎜⎜⎝

⎛∂∂

−×∇=×∇×∇

εμ

equal,so

Et

E oo 2

22

∂∂

=∇ εμ

Et

E oo 2

22

∂∂

=∇ εμ

Bt

B oo 2

22

∂∂

=∇ εμ

ftv

f 2

2

22 1

∂∂

=∇

displacement

velocity

8

cvoo

==εμ

1

et voila!

magnetic permeabilityelectricpermittivity

magnetic fieldelectric field

Electromagnetic wave

λ

9

n is a material parameter for chemists !

10

refractive index is complex

11

θ2n2

n1

θ1 θ1

A B

C

• no absorption (loss)• coherent light (ω)

2211 sinsin θθ nn = (Snell’s Law)

complex amplitudes ARB ⋅=

reflectance(depends on polarization)

Ray Optics Approximation

n

FresnelRTE , RTM

12

Geometric Optics Approximation

OP

TIC

AL

FIE

LD

INT

EN

SIT

Y

THICKNESS (nm)

n1 n2 n3

θ

ϕ

n2

1. thickness (t)2. polarization3. refractive index4. wavelength

• Critical angle sin θc = n2/n1

• For θ1 > θc |R| = 1 ⇒ e2iϕ

• so R tan ϕTE

tan ϕTM

reflected light is phase shifted

ck ω

λπ==

2

)sincos(2 θθ zxikne +±−

Propagation constant β = ω/vphase = kn2 sinθ

πφφθ mtkn 222cos2 132 =−−

OP

TIC

AL

FIE

LD

INT

EN

SIT

Y

THICKNESS (nm)

n1 n2 n3

Key Points for Raman (step index)

• enhanced path length • gain over backscattering• mode selection ⇒ spatial anisotropy• polarization state selection (TE, TM)• tensorial refractive index (anisotropy)• works for multi-layers (laminates)• relatively easy to simulate electric

field distributions• extract film thickness, refractive index• optical wave very sensitive to perturbations

Adjust Materials Parameters for Waveguide Raman Spectroscopy

13

Guided Wave Tutorial

n3 < n2 > n1

θ

ϕ

123

Coupling mechanism(prism)

Buffer

waveguide

TM

TE

3

Optical Chemical Bench

Single mode

OP

TIC

AL

FIE

LD

INT

EN

SIT

Y

THICKNESS (nm)

Raman scatter

n1 n2 n3

Guided Wave Tutorial

Prism coupling

TM

TE

Raman scatter

θ

ϕ

123

waveguide

3

θ

ϕ

1233

Grating coupling

microscope

spectrograph

grating

θ

1233

Butt coupling

fiberor lens

prism

14

Waveguide Raman Configurations

θ

ϕ1233

solid/fluid/hollowcore cylindrical

waveguide

solid/fluid/hollowslab/buried/ridge

waveguide

ComplexPIC toolbox

Silicon substrate

Buffer

Guide

UV

Photomask

Wet Etch

Cladding

Guide

15

OCM Module

DEMUX

* * *

Ch 1Ch 2

Ch 1, Ch 2, …, Ch 16

* * *

DETECTORARRAY

AMPLI-FIER

* * *

Packaged Device Interior

Functional Diagram

Polymer DWDM Optical Channel Monitor

Waveguide Coupling Configuration

M1

M2M3

L

λ/2

P

GT

H

θ

ϕ

123

Couplingprism

TM

TE

3

rotation axis

laser

prism

Si

16

17

Strategies must be combined . . .

Simulationslab, cylinder

numerical BPM(optical loss)

Microfabrication(simple/complex)

Materials(anything that

will guide)

Opticalcoupling

DetectionScheme

Specialcells

+ +

+ +

= WRS

Guided Wave Raman

• cw visible, near IR (FT versions)• enhanced path length• interfaces• non-destructive• SERS• flow cells• hyphenated experiments (EPR-Raman, . . .)• integrated optics formats (microfabrication toolbox)• CARS• laminates, monolayers, self-assembled structures• polarization state selective• “write-read” configurations; multiplexing• fluid/solid waveguides

Advantages

18

Guided Wave Raman

Challenges

• waveguide fabrication is everything !• artifacts (watch out!)• coupling• simulations• photochemistry• not turn-key• the usual things that plague Raman

Raman Waveguide Applications• photonics• biophotonics• plasmonics• microelectronics• environment• sensing (LOC etc)• forensics• nanoscience and technology

waveguideTE• Adsorption of proteins at surfaces• Ligand/receptor binding (antibody/antigen)• Immunosensing• Drug screening• Protein - lipid bilayer interactions• Protein - DNA interactions• Molecular self-assembly & nanoscience• Analysis of association and dissociation kinetics• Kinetics of adhesion, growth and spreading of

animal cells• Food monitoring

19

X(ZY)Z

yZ

y

x

Analyser

TM – TE Polarization mode conversion “reads” anisotropy

Pixels

ν CH modes

TE

TM

Spatial samplingalong waveguide

long axis

TE

TM

Rotational invariant

symmetric anisotropic

X(YY)Z δ2 4γ2/45

X(YX)Z 0 γ2/15

X(ZY)Z 0 γ2/15

X(ZX)Z 0 γ2/15

Interfaces: Guided Wave Resonance Raman

Otto et al, Appl. Spectrosc. 57, 12, 2003

Lab-on-a-chip: microfluiducs, micromechanics, integrated optics sensors Sub-monolayer

Cytochrome C

Depolarization ratios of cytochrome c as a function of the tilt angle θ, TE0 mode excitation

2ˆˆ PAK eeP ′⋅′⋅′∝ να

θ

air n=1.0

ZnO n=2.0

ϕ

SiO2 n=1.46

130 nm

20

θ

ϕ

B-A+

Ion Diffusion in Nanoporous Films

Hyphenated Experiments: neff mode spectroscopy + Raman

βm/k0 = neff,m

neff,m = n2 cosθm

Interfaces: Guided Wave Non-Resonance Raman

Otto et al, J. Phys. Chem., 100, 3288, 1996

22* ))0((||2/1)]0()0(Re[2/1 ===×== zfacNzHzEI mmmmm TETEoeff

TETETEsurface ε

Intensity at the interface

m = 0

m = 1

Thickness µm0.0 0.2 0.4 0.6 0.6 1.0

n= 2.2n= 2.0

n= 1.88 nm poly(styrene)

S/N ~ 60; 60 s collection time

θ

air n=1.0

ZnO n=2.0

ϕ

SiO2 n=1.46

120 nm

monolayer protein BA (adsorption kinetics)

21

Other Guided Wave Approaches

Advantages of optical technology - interferometryCommercial wavemeter : Michelson interferometer to accurately measure

optical wavelength and wavelength changes ~ Δ 1 pm

IO Mach Zehnder Interferometer

Cost premium attached to interferometers in telecom networks can often be justified – does this make sense for integrated optics in biophotonics?

22

Farfield INFO

Dual polarization laser interferometry. What questionsdoes it answer ?

The sensor chip showing schematically the binding of antigens to surface-boundantibodies. The laser beam addresses the device alternately (on a 50 Hz cycle) with transverse electric (TE) and transverse magnetic (TM) light. On the right, a camera image of a typical fringe pattern showing good contrast.

Far field pattern

optical coupling

single modewaveguides

Throw away a key axiom of traditional telecommunications optical waveguide design (namely that low device insertion loss is essential)

Far field pattern (Young’s double “slit” diffraction)

Measure perturbations to optical properties of a planar waveguide

Use evanescent field of a waveguide mode penetrating into the medium adjacent to the waveguiding film → surroundingmedium influences propagation velocity of guided mode

Guided mode described by the effectiverefractive index neff.

Changes in composition of medium will change neff

n2

n1

φ

θ

Interferometry with evanescent waves ?

23

Globular cell

Protein moleculeEvanescent wave withpenetration depth of ~ 100nm

Spread cell

cell close contacts

~ 10 μm

Schematic illustration of the adsorption of proteins and cellson waveguide: adsorbed proteins are completely within the penetrationdepth of the evanescent wave. After adhesion, cells spread and the area of close contact is increased.

Adsorption of proteins and cells

Grating

Effective index (neff) mode spectroscopy

• Kinetics adsorption/desorption (resolution ~seconds)• Can be coupled with Raman

Detection limits <1 ng/cm2 up to few hundred nanometers above the surface of the waveguide

Time

Ads

orbe

d m

ass

of p

rote

in

inject sample(neff) coupling angle shifts

due to change in neff

Light-mode spectrum

TM peakTE peak

Angle of incidence

OWLS

Hug et al., Biosensors & Bioelectronics 16 (2001) 865.874

24

Interfaces: Flow cell chip for crystal growth

inout

grating coupling

Real time evanescent waveguide Raman spectra of NaNO3crystallization

1000 1050 1100 1150

Gratings:UV writingHot embossingCold embossingEtching

Andrews and Yan (2007)

injection moldedplastic channel or metal housing

grating embossed in sol gelor polymer waveguide(optional prism coupling)

reflected diffracted modes

M-1M0 M+1

out coupled light incident light

fluid flow connections

Sol-gel or plastic chip flow cell structure

Grating coupled leaky mode waveguide microchannel chip

leaky modes guided by low refractive index medium (water @ ~ 1.33)

• no additional optical coatings

25

Meaure changes in the effective refractive index: Layer structure surrounded by the ambient medium A S – substrate; F – film; SL – sensing layer; C – cover; corresponding refractive indices (na, ns, nf, nl, nc) and thickness (hf, hl)

Chirped Grating Coupler Sensor

Tuned Filter

Sensitivity

Wiki et al., Biosensors & Bioelectronics 16 (2001) 37–45

Plasmonic devices

26

10 nm

Periodic charge oscillation around equilibrium (plasmon)

Plasmonic nanostructures enhance the cross section for optical events and function as optical couplers across the micro-nano interface

Plasmonics - the study and application of electromagnetic field confinement and enhancement via surface plasmonpolaritons (SPPs)

Natural oscillation frequency of metal nanoparticles allows for resonant excitation

Below resonance: small finite amplitude, and charge response in-phaseOn resonance: large amplitude and 90o phase lagAbove resonance: small vanishing amplitude, and 180o phase lag

10 nm

Light scattering strong near the nanoparticle plasmon resonance

27

Bioconjugated Nanoparticles

core-shell nanoparticle

Silica shell for:• bioimaging• high amplification• photostability• bioconjugation/biocomptibility

magnetic nanoparticle

linker

linker

linker fluorescent signaling

biocompatibility

antibodydetection

DNA

Design of the local environment of particles can be used to control the resonance for applications e.g. in biological labeling

28

Biodetection techniquesuse resonance shift due to binding (local epsilon change)use nanoparticles as tracersuse nanoparticle aggregation to detect cross-linkinguse fluorophore quenching as indication of DNA bindinguse surface enhanced Raman to identify molecules

Nanoparticles in medicineuse nps as local heat sourceuse nps as drug release agent

Otheroptical trapping of biomolecules

Nanoparticle plasmon-based approaches in biology and medicine

a dhesive benchn anopartic le opticaf ield inten sifier laym olecular adhesivewave guide

=

ω

2 ω Ag surfaceCS

NCH 3(CH2)17CH NHO ONCH3 (CH)21

Sχ= 4 x 1 0 es u(2) -8

D AASP

interfacial reaction

OpticalChemical Benchwaveguide

propagating polarized E-field

mesoscopic structure

auto-assembled

interfacial reaction

OpticalChemical Benchwaveguide

propagating polarized E-field

mesoscopic structure

auto-assembled

Bioconjugates

29

Watching Glass Grow with Nanoplasmonics

Waveguide RamanOptical Chemical Bench

Euplectella sponge , commonly known as the Venus Flower Baskethas an intricate cylindrical mesh-like skeleton of glassy silica At the base of the sponge's skeleton is a tuft of fibers that extends outward like an inverted crown. Typically, these fibers are between two and seven inches long and about the thickness of a human hair.

30

Glassy silica needles 2 mm x 30 µm produced by a marine sponge.

Each needle contains an occluded axial filament comprised of silicateins that catalyze and may spatially direct polycondensation of silicon alkoxides and silicic acid at neutral pH.

31

Proposed mechanism of catalysis of the rate-limiting step in tetraethylorthosilicate(TEOS) hydrolysis and polycondensationcatalyzed by silicatein

The Chemistry of Organic Silicon Compounds. Volume 3Ch 14, 2001

D. E. Morse

Postulated mechanism of amine-mediated silicicacid condensation.

N. Kroger, M. Sumper, in Biomineralization (Ed.: E. Baeuerlein),Wiley-VCH, Weinheim, 2000, pp. 151 ± 170.

32

Commandsurface

Raman

enhanced electric

field herewaveguide

Ag

TE

Interfaces: Optical Chemical BenchWaveguide SERS

Dipole limit

Molecular adhesive

Si

C

C

C

S

OO

H

H

H

H

H

H

O

Schematic structure of SPP polarizer

cladding

TM

TE

TE

Ag layer

buffer

coresubstrate

33

n= 1.5125

1 μm

n= 1.6150Ag

n= 1.4400

50 nm

TMo couples strongly to Ag overlayer

Re(Hy)

Guide

wav

egui

de

Ag

TMo

Maxwel-Garnettcomposite

TMn coupling depends on the waveguide structure

2D Ag colloid deposited by MSA on 3-MPTMS

substrate = SiO/SiO2

95 Å ave diameter11 Å interparticle distance106 Å centre-to-centre

34

300 500 700 900 Wavelength (nm)

Absorbance (arbitrary units)

Ag on waveguideExtinction

νs CH3

waveguide

Neat

ν SH

2400 2600 2800 3000Raman shift (wavenumber)

Inte

nsity

No Ag

CH2

CH2

CH2

S

Si

O O O

Molecular adhesive

Grafting enhanced

No fieldintensification

νs CH2

νs CH2 (fr)

νs CH3 (fr)

Thiolate anion/aqueous base

35

163.7 - 164.7 eV

Cu2+

4-mercaptopyridine

Ag

SH SH SH SH SH

SH

SH

3-MPTMS

Sulfur 2p XPS1/2,3/2

164 160168

Binding energy (eV)

Sensing

1650 1600 1550

IO-EWSERS of 4-MPy titrated by acid/base

pH 1

pH 6.4

pH 14

1617 1585

Raman shift (wavenumber)

cm-1 cm-1

N

S

N

S

H+

IO-EWSERS of 4-mercaptopyridine acid-base reaction

Nano pH SensorAndrews et al.Langmuir 1996, 12, 6389-6398

8b νC-C

commandsurface

36

γCCC 12a1

Si-O-Si EtOH

νsC-C-O

~ 440 cm–1

δ(Si–O–Si)symm. bend νas,s Non-bridging

Si-O ?

ZnO waveguide

Si(OH)

656 cm-1D

Raman shift (wavenumber)

S

NH2

+ H+ + Si(OEt)4

S

NH2

S

NH3+

S

NH3+

+ H+ + Si(OEt)4

(no change with TEOS + PMA alone)

7a1 9a1 19a18a1

commandelement

19b2 δ ν CC + CH (ip)

ν CC (ip)

3b2 δ CH + ν CC (ip) 9b2 δ CH

37

1596 8a (a ) 1 ccν

999 12 a 1 ccβ

1221

1231

1301

βCH 1027

Raman Shift ( cm )-112001000800 1400

waveguide Raman of PVA

Benzyl thiolate/Au FractalPVA Waveguide

Surface Enhanced Raman from

Inte

nsity

(arb

itrar

y)

S

SS

S

SS

S

S S

SS

SS

S S

S

SS

S

S

SSS

S

S

S

S

S

S

SS

SS

S

S

S S

S

SSS

S

S

SS

S

S

S

S

SS

S

S

S

SS

SS S

S S

S

SS

S

S

SS

S

S

S

S

S

SS

S

S

Nanocomposite Waveguide SERS

Liquid Core Waveguide Raman Spectroscopy

Burgess et al. Talanta 59 (2003) 809/816Anal. Chem. 1999, 71, 4808-4814

Walfaren, G. E.; Stone, J. Appl. Spectrosc. 1972, 26, 585-9;Appl. Spectrosc. 1975, 29, 179-85.

spectrograph

CCD

HPLC column

H2Opurge

waste

Raman Microscope

Raman waveguide flowcell (1M x 50 µm Teflon tube)

pump

waveguide50000 cts

vial

800 cts

1000x improvement in detection

38

Lab-on-a-chip

Ring Resonator

λ1 . . .λn λ1 . . .λn-1

λn

Guided mode in Through channel

Drop channel

39

Waveguides and Resonators

X. Fan (U. Missouri)

Optics Letters, Vol. 31, Issue 9, pp. 1319-1321 (2006)

Liquid Core Ring Resonator

40

Skin layer

Support layer

Asymmetric membrane (Graded Index Waveguide)

Depth z (µm)

Refractive Index n

1.4

1.44

1.48

1.52

1.56

0 2 4 6 8

CA

partiallyregenerated CA

RC

Ray optics representation Electromagnetic field profiles

Substrate

Film

Superstrate

Depth

Field Intensitym = 0

m = 1m = 2

m = 0 m = 1 m = 2

0

t

θθ1

t

θ2

θ0

Waveguide Membranes: LOC Applications

iWKB

Andrews and Kanigan, Lab-on-Chip, Roy. Soc. Chem,submitted, Oct, 2006.

n1

2

4

6

3

5O

H

O

R

H

HH

CH2R

HR

O

O

H

CH2RH

H

H

R

H

O

R

O CO

CH3OHR = or

Cellulose acetate repeat unit

Six cases ofUniaxial Symmetry

41

Summary of active Raman tensor components for polarized WRS measurements in the presence of artifacts.

αXZαYZαXY, αXXαYY, αYZMisalignment about Z-axis

αXZ, αXXαYZ, αYXαXYαYYMisalignment about Y-axis

αXZ, αXYαYZ, αYYαXY, αXZαYY, αYZMisalignment about X-axis

αXZ, αXXαYZ, αYXαXYαYYLongitudinal field component

αXZ, αXYαYZ, αYYαXY, αXZαYY, αYZTE ↔ TM mode conversion

αXZαYZαXYαYYIdeal geometry(no artifacts)

IXTMIYTMIXTEIYTE

Polarized WRS measurementSource of Artifact

Waveguide Raman spectra of CA. Difference spectrum X(YX)Z – X(ZX)Z is shown at the bottom.

Artifacts in WRS Andrews and Kanigan, Lab-on-Chip, Roy. Soc. Chem,submitted, Oct 2006.

Light Induced Self Inscription(Chemical “Solitonics”)

42

Self-writing - the process of forming waveguide structures within a materialin which a guided wave creates its own (permanent) waveguide

diffraction thresholding focusing

Broadening bydiffraction/dispersion

Self inscription with self-focusing self-trapped soliton

Distinguish different kinds of wave propagation

This index change acts like a lens to the light and so the beam focuses. When the self-focusing exactly compensates for diffraction of the beam we get a soliton

A permanent local increase in refractive index occurs.The change in refractive index is proportional to intensity. A graded index is initially formed in the material with a maximum along the axis of the propagating laser and decreasing radially. This change in refractive index causes the laser beam to be more strongly guided along the propagation axis (self-focusing) and leaves a permanent structure inscribed in the medium (self-inscription).

43

x RlE(OR′)n-l + y E(OR′)m + z H2O → RqEOp + w R′OH

Ti

F

F

FF

F

FF

F

FF

Ti

F

F

FF

F

FF

F

FF

hν

Δ

Si

OCH3

CH3OCH3O

O

O

Zr(OPr)4

O

O

H

+

+

Light Induced Self Inscription (LISI)

photoinitiator

H+

Andrews et al, SPIE, 2005, 5924.

POLARIZED WAVEGUIDE RAMAN SPECTROSCOPY

y

TM polarization along Z

TE polarization along Y

X(YY)Z

X(YX)Z

X(ZY)Z

X(ZX)Z

yz

y

x

Analyser

2800 2900 3000 3100

X(YY)Z

X(ZX)ZX(YX)Z

X(ZY)Z

WAVENUMBER (cm-1)

INT

EN

SIT

Y

CH stretching modes

z

x

2ˆˆ PAK eeSignalRaman ′⋅′⋅′∝ να

44

δ-CH ip νC=C νC=O(sat)

Guided Wave RamanSelf-inscription/self-focusing

Saravanamuttu and Andrews, OPTICS LETTERS 27(15), 1342, 2002

Pro

gres

s of

pho

toin

scrip

tion

Optical “Read” of Chemistry of Self-Inscription(LISI)

Self-Inscribed Fiber-on-Chip

After 8 hour exposure

Top view of parallel self-inscribed waveguides

Rounded Profile

~10 μm

~100 μm

~6.5 μm

5 μm

45

LISI Experimental Set-up forself-writing and optical “read”

sample

rot. arm

Laser

BS

rot. arm

M1 M2

M3M4

M5

sample

46

Optical Cross – 3o crossing angle

Mutual trapping of self-inscribed counterpropagating optical beams. Leftmost image is of the experiment in progress. Centre digitized images show the progression of the inscribed waveguides to the point where they mutually interact. Rightmost image shows the 3D waveguide.

α = 3o

a = beam half width

L = distance betweenX-section beaminput

k = 2π/λ

2L/ka2

x/a

Icr

47

Optical Cross – 7o, 12o crossing angle

Periodic Structures

48

Optical Self-Inscription – Stability Regime

Increased stability atlow power, short

exposure time and lownetwork modifier (ZrO2) content

Self-inscribing guidedwave (stable regime)

t = 0.985 µm

n633 =1.515

Andrews and Belanger,Opt. Lett., submitted

Self-inscribed Corrugations - AFM analysis

~ 8µm

Sukhorukov et al

Optical beating alonga self-written waveguide

at low threshold

AFM measurement of beat length

Andrews and Belanger,Opt. Lett., submitted

Wet etched

49

Light propagation in a 18 µm-thick liquid crystal cell for a voltage of 1.6 V: (a) for 1.5 mW; (b) for 4.5 mW

Periodic intensity fluctuations

Non-solitonic, non-local

Soliton-like beam propagation in planar cells of nematic liquid crystals

Periodic modulation due to oscillations of the beam width along the thickness when propagating through liquid crystal

Beeckman et al., OPTICS EXPRESS, Vol. 12, No. 6 / 1011

Power increased from16 to 550 µW

Instabilty Regime- Filamentation“Freezing” filamentation

50

What am I holding ? (Indeed, what am I wearing ?)

This gentleman tries to hide a knife behind a news paper. THz imaging penetrates through most clothes and inorganic species, except water. Water absorbs extremely well at THz frequencies.

Polaritonics• intermediate between photonics and electronics• signals carried by phonon-polaritons ⇒ admixture of electromagnetic and

lattice vibrational waves

• polaritonics bridges the gap between electronics and photonics

1 GHz 10 GHz 100 GHz 1 THz 10 THz 100 THz 1 PHz

Photonics

exciton-polaritonsphonon-polaritons

PolaritonicsElectronics

magnon-polaritons

free charge current bound charge current/waves waves

51

Where do we need THz sampling?

∫= )(tdtFp vvδ

Generating Phonon-polaritons:momentum imparted by pulse

)}()(Re{ * ttFj

vijjv εαε=

0=⎟⎟⎠

⎞⎜⎜⎝

⎛

∂

∂=

Qvv

Qijv

ij Qα

α

ISRS

Wedge excitation

Point excitation

52

53

Polariton field splitting and recombination in a waveguide interferometerin lithium tantalate.

√εμ = √(-|ε|)(-|μ|) = √eiπ|ε|eiπ|μ| = eiπ√|εμ| = -n

Metamaterials

54

θ2n2

n1

θ1 θ1

A B

C

• no absorption (loss)• coherent light (ω)

2211 sinsin θθ nn = (Snell’s Law)

complex amplitudes ARB ⋅=

reflectance(depends on polarization)

Ray Optics Approximation

n

FresnelRTE , RTM

positive index.cfm negative index.cfm

Probing Negative Index Materials

n =√εμ < 0 ⇒

positive n negative nPavel Kolinko and David R. Smith 2003 / Vol. 11, No. 7 / OPTICS EXPRESS 640

reversed geometrical optics, reversed Doppler shifts

metamaterial

55

Superlens

source eiωt

n ≥ 1

elec

tric

field

distance

dist

ance

n ≤ -1 n ≥ 1

image

perfect lensevanescent field

~perfect lensevanescent

field

regular lens evanescentfield

propagating planewave component

negative refraction

Webb, Yang, Ward and Nelson, Phys. Rev. E 70, 035602(R) (2004)

PHOTONIC NANOPOLIS

56

White opal

Opal beads Black opal

Rough opal

Carved opal

OPAL

OPAL is derived from "upula," the Sanskrit word for precious stone

57

The origin of color in opal has given rise to as many theories as there are stories concerning the stone's history. However, it has now been demonstrated that a regular array of spheres and voids diffracts white light by breaking it into the complete range of spectral color. The color observed is primarily dependent on the layer spacing, which is determined by sphere size.

Water is trapped in layers among rows of silica glass spheres. Well, depending on how big the spheres are, and what's between them, they act as a prism! That's why when you turn an opal, you may see so many different colors.The color observed also depends on the angle of incidence of light and the position of the observer.

What is a CRYSTAL ?

a

These are all crystals

58

dA

B

C

θθ

θ

A B

dθ

nλ = 2dsin θ

Crystals diffract light

What is a CRYSTAL ?Photonic

Periodic structure that reflects light

Opals are natural examples – distinctive color is due toreflection caused by a photonic gap in the “crystal”

59

Conventional mirrorreflects light Photonic crystal reflects

selected wavelengths

Stacks of mirrorsThis band of wavelengths is stopped

Photonic crystal reflectsselected wavelengths

Stacks of mirrors

Stopped band of wavelengths

PHO

TON

EN

ERG

Y

StopBand Gap

Photonic band of energies

Photonic band of energies

60

ELEC

TRO

N E

NER

GY

ElectronicStopBand Gap

Electronic band of energies

Electronic band of energies

PHO

TON

EN

ERG

Y

PhotonicStopBand Gap

Photonic band of energies

Photonic band of energies

PHOTONIC crystals are a lot like semiconductor crystals !!

Photons with these energiesare forbidden

This is wherephotons conduct

This is whereelectrons conduct

How do we make photonic crystals?

Make Opals !!

61

This is a molecular view of a fragment of silica glass

Not very “ordered” is it ?

62

Examples of photonic crystals generated by means of holographic lithography

SEM image of a polymeric photonic crystal generated by exposure of a 10 micrometer film of photoresist to a four-beam laser interference pattern. The top surface is a (111) plane; the film has been fractured along a cleavage plan of the photonic crystal structure.

63

Photonic Crystal Ring Resonator

Perfect Waveguide Bends

A linear defect is created in the crystal which supports a mode that is in the band gap. This mode is forbidden from propagating in the bulk crystal because of the band gap. So, if one makes a bend, the wave follows with 100% transmission !!

PHO

TON

EN

ERG

Y

StopBand Gap

64

• Guiding light: Conventional Optical Fibres

Cladding

Core

nCore>nCladding

nCladding<nCore

nCore

Total Internal Refection

• Guiding light: Conventional Optical Fibres

• Bragg reflection– Very low losses

• But– Bandwidth ?– Angle of incidence ?– Index contrast ?– Fabrication ?

65

Burak Temelkuran et alNature 420, 650-653, December 2002.

• Bragg fibres, “OmniGuide” fibres

• “Generalized Bragg reflection”:Photonic Crystals

• Periodicity in 2D (or 3D)

66

• Photonic Crystal Fibre PCFs

Λ

dHoles

Silica (or other)

Core : - hollow- solid

Photonic Crystal

Birks, Roberts, Russel, Atkin, Shepherd, Electron. Lett. 31, 1941-1942 (1995)

N.A. Mortensen, Opt. Express 10, pp. 341-348 (2002)B. Kuhlmey et al, Opt. Lett. 27, pp. 1684-1687 (2002)

• Intuitive interpretation : the “mode sieve”

Fundamental modeSecond mode

|Ez|

Simulations: CUDOS MOF Utilitieshttp://www.physics.usyd.edu.au/cudos/mofsoftware/

67

• Fabrication: “stack and draw”C

rystal Fibre A/S

OFTC

, Sydney

Bla

ze P

hoto

nics

• Fabrication

Knight, Birks, Russell, Atkin, Photonic crystal

fiber

Cregan et al.Photonic bandgap fiber

1974 1996 1999 2004

Kaiser et al.Air-silica fibers

Mangan et al, OFC 2004(1.7dB/km Loss@1550nm)

68

• Hollow core and solid core PCFs

Mangan et al, OFC 2004(1.7dB/km Loss@1550nm)

APPENDIX

REFERENCE LIST

69

1. Ben Fry “Organic Information Design”http://acg.media.mit.edu/people/fry/

2. Canadian Optical Internet (Project Canarie): http://www.canarie.ca/canet4/

3. Classic papers on Waveguide Raman: 1. Y. Leng, I. Imbert, J. Cipiani, S. Racine and R. Dupeyrat, Opt. Commun. 11, 66 (1974); J. Phys. (Paris), Colloq. C5 38, 253(1975). 2. R. Dupeyrat. Ber. Bunsenges. Phys. Chem. 85, 490 (1 981 ). 3. J. D. Swalen, J. Phys. Chem. 83, 1438 (1 979). 4. J. F. Rabolt, R. Santo and J. D. Swalen, Appl. Spectrosc. 33,549 (1 979) ; 34‘51 7 (1 980). 5. J. F. Rabolt, R. Santo, N. E. Schlotter and J. D. Swalen, 1BMJ. Res. Dev. 26, 209 (1 982). 6. J. D. Swalen and J. F. Rabolt, J. Phys. (Paris), 44, C10-15(1983).7. J. D. Swalen and J. F. Rabolt, in Spectroscopy of Surfaces, edited by R. J. H. Clark and R. E. Hester. Vol. 16. Chapt. 1, Wiley, Chichester (1 988)

4. Guided wave resonance Raman - Otto et al, Appl. Spectrosc. 57, 12, 2003

5. Farfield Inc sensors: http://www.farfield-scientific.com/index.asp6. Guided wave Non-resonance Raman: Otto et al J. Phys. Chem., 100, 3288, 19967. Optical waveguide light mode spectroscopy: using optical waveguides and diffraction

gratings to measure protein adsorption - Biosensors and BioelectronicsVolume 18, Issue 4 , April 2003, Pages 415-428

8. Nanoplasmonics and core shell nanoparticles: see www-ece.rice.edu/~halas/pubs.html Also Andrews et al Langmuir 1997, 13, 3744-3751 and Langmuir 1996, 12, 6389-6398

9. More on Nanoplasmonics – from Nanoplasmonics Vladimir M. Shalaev(Editor), Satoshi Kawata (Editor) Published:January 2007, ISBN:0444528385; also the review article in JOURNAL OF APPLIED PHYSICS 98, 011101 2005

Bio-plasmonics: Nano/micro structure of surface plasmon resonance devices for biomedicine in Optical and Quantum Electronics (2005) 37:1423–143

10. Biological optical fibres Proc Nat. Acad Sci, 3358–3363 March 9, 2004 vol. 101 no. 10.11. Lab-on-a-chip: Lab-on-a-chip with integrated optical transducers, Lab Chip, 2006, 6, 213–217.12. Ring resonator sensors: Optics Letters, Vol. 31, Issue 9, pp. 1319-1321 (2006)13. Polaritonics: PhD Thesishttp://www.people.fas.harvard.edu/~dward/Ward2005Thesis.pdfalso,David W. Ward, Eric R. Statz, Keith A. Nelson, Ryan M. Roth, and Richard M. Osgood:Terahertz wave generation and propagation in thin film lithium niobate produced by crystal ion slicing, Appl. Phys. Lett. 86, No. 2, 022908 (2005) DOI:10.1063/1.1850185. David W. Ward, Jaime D. Beers, T. Feurer, Eric R. Statz, Nikolay S. Stoyanov, and Keith A. Nelson: Coherent control of phonon-polaritons in a THz resonator fabricated with femtosecond laser machining, Opt. Lett. 29, 2671-2673 (2004). T. Feurer, Joshua C. Vaughan, and Keith A. Nelson:Spatiotemporal coherent control of lattice vibrational waves, Science 299, 374-377 (2003). Nikolay S. Stoyanov, David W. Ward, Thomas Feurer, and Keith A. Nelson:Integrateddiffractive THz elements, Appl. Phys. Lett. 82, No. 5, (2002). Nikolay S. Stoyanov, David W. Ward, Thomas Feurer, and Keith A. Nelson:Terahertzpolariton propagation in patterned materials, Nature Materials 1, 95-98 (2002).

70

14. Metamaterials with negative refractive index: see Webb, Yang, Ward and Nelson, Phys. Rev. E 70, 035602(R) (2004) and references cited therein15. Photonic Crystals: Key book is “Photonic Crystals”Publisher: Princeton University Press (1995) ISBN-10: 0691037442 or ISBN-13: 978-0691037448 ; also “Foundations of Photonic Crystal Fibers”by Zola et al., Imperial Coll. London Press, ISBN 1-86094-507-4 ; hundreds of literature references otherwise

Other references – General1. “Guided wave Photonics” Buckman, publ, Saunders1992, ISBN 0-03-033354-72. Fundamentals of Photonics, by Saleh and Teich, Wiley, 1991, ISBN 0-471-83965-5