Recent Progress in Photonic Crystals and Their Device Applications
Photon, Electron, Band Symposium on the Diversity of Opto-Electronics In honor of Eli Yablonovitch on his 65th Birthday RecentRecent ProgressProgress ofof PhotonicPhotonic CrystalsCrystals andand TheirTheir DeviceDevice ApplicationsApplications
SUSUMU NODA Department of Electronic Science and Engineering, Kyoto University OutlineOutline
・ Review of progresses in 3D and 2D photonic crystals I. Status of 3D Photonic Crystal Research in the early 1990s II. Developments of 3D Photonic Crystals III. Manipulations of Photons by 3D Crystals IV. Extension to 2D Photonic Crystals V. Breakthrough in Semiconductor Lasers VI. Thermal Emission Control ・ Summary and Perspective II．．StatusStatus ofof 3D3D PhotonicPhotonic CrystalCrystal ResearchResearch inin thethe earlyearly 1990s1990s 1. The crystals developed at that time had been limited to the "microwave" regime, even though the word of "photonic" was used. 2. It had not been clear what photonic crystals can do exactly and how photonic crystals can manipulate photons.
Issues: 1.Developing photonic crystals at optical wavelengths 2. Demonstrating what photonic crystals can do by using the developed crystals step by step. II.II. DevelopmentsDevelopments ofof 3D3D PhotonicPhotonic CrystalsCrystals
Alignment and Stacking by Wafer Fusion
GaAs (or InP) (d) Removal of AlGaAs (or InGaAsP) GaAs (or InP) unnecessary Sub. substrate (a) Growth
(e) Alignment and (b) Formation of stacking. Stripes Repetition of (c), (d).
Nanometer scale (b) Wafer fusion (<50nm) 3D Fabrication Development of Alignment and Stacking System
Magnified view of microscope
Overview image Developed 3D Photonic Crystal
Reflection Transmission =0º =0º =10º =30º =20º =40º 100 100
10-1 10-1 m Reflectance Transmittance 10-2 10-2
1000 10 1200m 1400 1600 m Wavelength (nm) 700nm 10m S. Noda, et al., Science 289 (28 July 2000) 604 K. Ishizaki and S. Noda, Nature 460, 367 (2009) III.III. ManipulationsManipulations ofof PhotonsPhotons byby 3D3D CrystalsCrystals 1. Spontaneous emission control 0.7 A
A m
PC 0.7 B
m B
PC 0.7 C m C
0.7 PC
D m 0.7m D PC 0.7 E
Inhibition of m E emission
0.7 PC
Strong emission m F F PC
0.7 G G PC 10dB
Ogawa, Noda, Science 305, 227 (2004). m Noda, et al, Nature Photonics,3, 129 (2007) 1.2 1.4 1.6 wavelength/m Surface Modesaregenerated Frequency (c/a) without Surface Band StructureofInfiniteCrystal 0.20 0.25 0.30 0.35 0.40
0.20 0.25 Frequency0.30 (0.35 c/a) 0.40 M M PC Air Wavenumber Wavenumber Air light-lin 3. LightControlatSurface 2 e
-M direction X a X 1 1 M X M X 0 | 2 2 E| Max Nature K. Ishizaki, S.Noda, etal, Air light-line M M 460, 367 (2009). physics related surfacephoton effect ofmetals andthe surface plasmon-polariton Interesting relevancetothe z y x y y x x a X 2 2 m M X 1 Surface 0 Max IV.IV. ExtensionExtension toto 2D2D PhotonicPhotonic CrystalsCrystals
Calculation and Fabrication Techniques developed for 3D Photonic crystals also induced Rapid Progress in 2D Photonic Crystals.
0.4
0.3
0.2
0.1 FREQUENCY[c/a]
0 XJ 2D Photonic Crystal 2D Bandgap Manipulation of Photons by 2D Photonic Crystals
A. Fundamental of Manipulation of Photons B. Photonic Nanodevices C. Concept to Increase Q Factor D. Dynamic Q Factor Control of Nanocavity and Stop Light E. Raman Scattering in high-Q Nanocavity F. Toward Quantum Application G. Extension to New Materials A. Fundamental Building Block to Manipulate Photons Trapping and emission of photons
fi m
250nm
Si on Insulator a=420nm
fi
=0.4nm Q=3800 Intensity (a.u.)
f1, f2, fi,… S. Noda, et al, Nature 407 1500 1550 1600 (2000) 608. Wavelength (nm) B. Photonic Nanodevices (Heterostructure)
Song, Noda, et al, Science 300, 1537 (2003) C. Finding of Concept to Increase Q factor of Nanocavity
Q=3,800 Shift Q>40,000
Akahane, Asano, Song, Noda, Nature (Oct., 2003) Key Point to Increase Q factor of Nanocavity “Gentle Confinement” Starting Cavity Structure L=2.5 Abrupt GaussianGentle Nanocavity
0 0 Electric field [a.u.] Electric field [a.u.]
-10 0 10 -10 0 10 Real space coordinate [] Real space coordinate [] a=420nm Leaky region
0 0 electric field [a.u.] field electric electric field [a.u.] field electric Fourier transformed Fourier transformed -10 -5 0 5 10 -10 -5 0 5 10 Wave vector [] Wave vector [] 2D PC Slab Photonic Double Heterostructure
For Ideal Gaussian Confinement a a a a1 1 2 1 a１=410nm a２=420nm +
0 PC-I PC-II PC-I PC-I - I II I Photon )
) Confinement 2 2 a a Almost Gaussian- like Confinement Transmission Transmission
Mode Gap Mode Gap Frequency (c/ Frequency (c/ Real space-5 0 5 Real space Space (a2)
B.S.Song,Highest S.Noda, Q of 4,300,000 et al, Nature has Materials been achieved(Feb., 2005) D. Dynamic Q Factor Control of Nanocavity
I) When we introduce photons into nanocavity, ----- Q should be Small II) Once the photons are introduced into the nanocavity, ----- Q should be Increased Rapidly
III) When we release photons from nanocavity ----- Q should be decreased rapidly
Dynamic Control of Nanocavity Q Mechanism of Dynamic Q Control
Tanaka, Noda, et al, Qv Nanocavity CLEO/PR 2005 and Nature Materials, 2007 Refractive Index Change Perfect Mirror Qin
Waveguide Interference (Phase Difference: ) Constructive: Leakage to the waveguide increasesQ and Q decreases /Q/ [11 ino in 1] Q/ total Destructive cos1 : Leakage to the vwaveguide is suppressed and Qin increases dramatically
Q can be changed from min (Qin0/2) to max (Qv) by changing from 0 to Stop Light (On-chip Catch & Release Operation of Optical Pulse)
Release Pulse Trap pulse F. Extension to New Material Suppression of Undesired Nonlinear Phenomena (TPA) Si-Based Nanocavity
Serious Two Photon Absorption Problem Introduction of Silicon Carbide (SiC)
SiC
waveguide cavity
Near-field pattern 1450 1500 1550 1600 Intensity (a.u.)
1450 1500 1550 1600 Wavelength (nm)
SiC
5 m 1 m Operation in Wideband Frequency Regime
SiC (Electronic Bandgap of 2.2-3.2 eV) G. Quantum Application (I) (I) High-Q Nanocavity + Quantun Dots
Quantum dots
Akahane, Noda, et al, Nature (2003)
Nano-lasers and Strong Coupling Phenomena Caltech: Yoshie, et al, Nature (2004) UCSB: Strauf, et al, Phys.Rev.Lett. (2006) ETH: Hennessy, et al, Nature (2007) Tokyo: Nomura, et al, Optics Exp. (2007) Stanford: Vuckovic, et al, Nature (2007) (see also Noda, Science (13 Oct. 2006)) F. Quantum Application (II) (II). Strong Coupling between Nanocavities themselves (and Its Dynamic Control)
Ex: Quantum gate using coupled cavities (Proposal) Waveguide 2 xy Waveguide 1
Mx My
M3 34 4y 5x 56 M6
2 2 2 2 Cavity 3 Cavity 4 Cavity 5 Cavity 6 Target qubit Control qubit |x› |y› 2 QD QD 2
0 0 2 2 |g› |x›-|g› |y›-|g› Strong coupling between nanocavities at distant positions
For realizing flexible architecture and on- demand dynamic control without cross talks Cavity A Cavity B
Realization of strong coupling between nanocavities through a waveguide while concentrating photons in nanocavities not in the waveguide The Condition
Relationship between escape time from nanocavity to waveguide in, and photon propagation time through the waveguide Tp:
in >> Tp Condition of round trip phase difference between nanocavities through the waveguide: = (2m+1) Calculated Results Cavity A Cavity B Cavity A Cavity B Waveguide Enegry (a.u.)
0 100 200 Time (ps) Preparation of Sample
a Reflector C Reflector D Cavity A Cavity B Waveguide 202a=82.8 m 17a=7.0 m
b c
w1 w w2 Si w3
. 351 aw Multistep Nanocavity 3aw 1 . 350 aw 2 . 370 aw 3 Experimental Results (Strong Coupling)
Spectral Regime
150 pm
3.3 pm 3.3 pm Intensity (a.u.) Intensity
1539.3 1539.4 1539.5 1539.6 Intensity (a.u.) Wavelength (nm) 1536 1538 1540 1542 Wavelength (nm)
Time Domain Measurement
Cavity A Cavity B Intensity (a.u.)
0 100 200 300 400 500 Time (ps) Experimental Results (Dynamic control) Control light
Cavity A Waveguide Cavity B
Cavity A Cavity B Intensity (a.u.) Intensity (a.u.) 0 100 200 300 400 Time (ps) Cavity A Time (ps) Cavity B First observation of dynamic control of coupled state between high-Q nanocavities Intensity (a.u.) Sato, Noda, et al, Nature Photonics, (Jan. 2012) 0 100 200 300 400 Time (ps) IV.IV. BreakthroughBreakthrough inin SemiconductorSemiconductor LasersLasers Broad Area Control of Photons
A. Perfect Single-Mode Broad-Area Oscillation B. Generation of Unique Beam Patterns C. Blue-Violet Surface-Emitting Oscillation D. High-Efficiency and High-Power Operation E. Beam Steering Functionality A. Perfect Single-Mode Broad-Area Oscillation Device structure and lasing mechanism Surface emitting region Electrode Contact layer Upper clad B Photonic crystal Carrier block Active layer A Lower clad
Electrode Substrate
Imada, Noda, et al, APL 75 (1999) 316 Noda, et al, Science 293 (2001) 1123 -X
-M
Perfect Single Mode Oscillation
Surface Emission
Inplane Couling Device fabrication InGaAs/GaAs System
Fused Interface Electrode p-GaAs Contact 50x50m2 p-AlGaAs Clad Photonic Crystal p-AlGaAs Carrier Block InGaAs Active
n-AlGaAs Clad
Electrode Electrode Side View Top View Near-field pattern and lasing spectra
Broad Area Coherent Lasing Oscillation B. Generation of Unique Beam Patterns
Surface Emission
Inplane Couling Beam pattern control
Phase shift Phase shift
Phase shift Phase shift y
x Phase shift + Max. 0 - Max. Phase shift
Far-field interference should be changed A range of beam patterns are expected to be generated Engineering in crystal structure and beam pattern
287nm 1° 29.2m m 29.2
29.2m
Miyai, Noda, et al, Nature, 441, 946 (2006). Two types of doughnut beams
Beam Pattern 1º
:Polarization :Polarization
Tangential Radial Polarization Polarization Doughnut beam with radial polarization
Tight Focusing Operation
High NA Lenz.
Component Remains
Tight Focusing by much smaller than wavelengths is Expected C. Blue Violet Surface-Emitting Operation InGaN/GaN system
Near- and Far-Field Patterns
m p-contact p-AlGaN cladding InGaN MQW Before Injection 2D GaN/Air PC Top n-AlGaN cladding Before CurrentView Injection Near Field Pattern (Lasing Oscillation) n-GaN substrate n-contact Magnify
1 degree ドーナツ状のビーム
Far-field pattern Matsubara, Noda, et al, Science 319, 445 (2008). D. High-Efficiency and High-Power Operation Control of unit cell structure
z y z Doughnut Beam Circular Cancellation Cancelled-Out Beam Suppressed x
y y y x x x Unit cell structure and efficiency (Operation wavelength: 980nm)
Rectangular 250 (pulse 500ns, 1kHz) triangle 200
150
100 triangle
50 PEAK POWER (mW)
0 0 100 200 300 400 500 CURRENT (mA) Circle Optimization of device configuration and introduction of interface effect Emitting region P-electrode
P-clad Active d N-clad
N-electrode Reflector Reflectance Upside-Down Configuration and Introduction of Interference Effects between Downward and Upward Emitting Light E. Beam-Steering Functionality
· Important for wide range of laser applications
・・・
· Achieved using complicated optical systems Galvanometer Polygon mirror MEMS mirror Limit ・ Speed ・ Size ・ Lifetime [1] [3]
[2] [1] J. Montagu, Handbook of Optical and Laser Scanning, pp. 417-476, Marcel Dekker (2004). [2] G. Stutz, Handbook of Optical and Laser Scanning, pp. 265-297, Marcel Dekker (2004). [3] A. D. Yalcinkaya, et al.,, IEEE J. Microelectromechanical systems 15, 786-794 (2006). Composite photonic crystal
Square lattice photonic crystal
Air hole
Composite photonic crystal
Air hole -X2 -M a
-X1 a
Rectangular lattice photonic crystal -X2 -M
Air hole -X1
a a' a'
-X2 -M aa a
-X1 a’ Device structure and Fabrication
~1000 m ~300 m
Composite photonic crystal
-X2 Active layer n-Electrode -X1 Periods k
426 nm 0.15 a′ Continuous change a 294 nm 0 a: Fixed Position a’: Continuously changed (Spatially changed) Experimental Results
-30° +30°
Angle, (deg) Kurosaka, Noda, et al, Nature Photonics (July 2010) SummarySummary andand FutureFuture ProspectsProspects
Various new concepts and technologies have been built up in the field of photonic crystals
Now is the time to take on new challenges to achieve ultimate light control based on photonic crystals, in order to realize novel communication and information processing technologies based on the quantum nature of photons, and to develop ultimate broad area coherent lasers, ultrahigh efficient light-emitting devices, sensors, displays, etc.