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ODae Kwon Department of Electrical Engineering Pohang University of Science and Technology Pohang 790-784, Korea

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Presentation on theme: "ODae Kwon Department of Electrical Engineering Pohang University of Science and Technology Pohang 790-784, Korea"— Presentation transcript:

1 ODae Kwon Department of Electrical Engineering Pohang University of Science and Technology Pohang , Korea IEEE-LEOS 2008 Nov. 11, 2008 (GaN) Photonic Quantum Ring Laser & Mega-Pixel Laser Chip for Display [Whispering Cave Mode]

2 2-D Whispering Gallery vs. 3-D Whispering Cave toroidal cavity 3D TIR 3D WCM prop. of PQR PQR from carrier-photon couple Single Mode Red PQR Laser Blue PQR Laser Laser TV [model]

3 St. Paul cathedral : Lord Rayleigh concave Whispering Gallery – Bessel function 2D TIR (Total Intnl. Reflecn) - 2D symmetry

4 Micro Whispering Gallery Mode(WGM) SiO 2 WGM 1910 Lord Rayleigh. WGM from concave surface Philosophical magazine, xx (1910). 2D TIR 1992 A.F.J. Levi, R.E. Slusher et al. 2D WGM microdisk lasers (thumb-tack), Appl. Phys. Lett. 60, 289 (1992). 2D TIR 1998 J.C. Ahn, et al., ODae Kwon. 3D WGM lasers by using naturally produced toroidal cavity in cylinders 3D TIR (whispering cave mode:WCM) Phys. Rev. Lett. 82, 536 (1999); SPIE (1998) 2003 D.K. Armani et al & K.J. Vahala. WGM by using laser-baked toroid-shaped cavity Nature. 421, 926 (2003). 3D TIR possible WCM Bessel (J m ) field profile Helical wave

5 Epi structure N-DBR P-DBR Active layer Silicon nitride coating SiNx substrate Planarization using polyimide Polymide Vertical mesa using CAIBE Ar: Cl2: BCl3 (3D WCM) PQR fabrication & structure CF4 SiNx etching by RIE for metal contact

6 CMP-Metal-WireBond-Packaging P-metal N-metal (3D WCM) PQR (concave) & PQR hole (convex) Ion implantation for hole isolation H + -Ion Implantation Hole etching, passivation Metal contact PQR hole OPTO Paper # :Mega-pixel PQR hole chip : PC eff. isolations

7 Photonic Quantum Ring z P-DBRs N-DBRs ρ P-metal MQW Temperature stability (T 1/2 dependent) A. Yariv. APL, 53, 12 (1988). Bessel (J m ) field profile Helical wave 12, near the PQR threshold 11.5, below VCSEL threshold 12.2, above VCSEL threshold Low threshold current ( ϕ =15 μm) Ahn et al., PRL, 82, 536 (1999).

8 PQR Threshold I th ( ) I. QW assumption II. QWR assumption W Rayleigh λ/2 # of wires A. Yariv. APL, 53, 12 (1988) (2.4) (4.85) Park et al., APL, 79, 1593 (2001). Ahn et al., PRL, 82, 536 (1999). Kwon et al., APL, 89, (2006). Chin-Chu-Ho, JAP 75,3302(1994) PQR mesa: (threshold) (transparency) PQR hole: (threshold) (transparency)

9 Spectral PQR Analy. of 3D WCM theoy Opt. Lett. Vol. 28, 1861 (2003)

10 PQR: carrier-photon dynamic model evanescent region Toroidal cavity z x 0 z=L x=W Bessel (J m ) field profile Helical wave Park et al., APL, 79, 1593 (2001). E. Gehrig et al., APL, 84, 1650 (2004). Dynamic filamentation and beam quality of quantum-dot lasers E. Gehrig and O. Hess, APL, 84, 1650 (2004). Stripe of W Rayleig h

11 Field intensity Carrier distribution Carrier Field ~ 5 [#] W Rayleigh ~1 µm, ϕ = 30 µm [MEJ,2008] psec x time Stripe of W Rayleig h

12 P. Avouris, Physics Today, 11, 17 (1993). M. F. Crommie, et al. Nature, 363, 524 (1993). Quantum corral of electrons Electron standing waves in a 2DEGs Coherent branched electron flow in a 2DEGs Period:15Å Room temp 1.7K Au(111) surface M.A. Topinka, R.M. Westervelt, E.J. Heller, Imaging Electron Flow", Physics Today 56, 12 (2003). Local density of states in 2DEG

13 Polarization Vectors // PQR : linear polarizer : +135 o fiber ( a): without polarizer (b): polarizer (c): polarizer (d): +45 o polarizer (e): +135 o polarizer Kim et al., JAP, 102(5), xx (2007 ). =15 μm, I=150 A (10kHz) Strong Carrier-Photon Coupling

14 Single mode PQR Laser JAP (2008) to appear 500 nA 1 uA 3 uA 5 uA

15 Red PQR Laser Array PQR emission LED emission 256 array ( = 7 m) Spacing = 68 m 256 array ( = 10 m) Spacing = 68 m I = 2 mA (7.8 A/cell ) - The PQR lasing region is brighter than the LED emission region, which means very high emission efficiency of the PQR laser.

16 Blue PQR laser at 480nm

17 PQR array (, spacing) CW/ room temp /at 60mA : without & with an attenuation filter

18 Blue PQR Laser LLO & dielDBR Structure 20um SiNx Ti/Al

19 Multimode PQR Lasing PQR LED

20 GaN Surface-Emitting Laser at Blue Wavelengths H. M., S. Yoshimoto, et al., & S. Noda Science 25 Jan. 2008: Vol pp. 445 (GaN)–PhC-SEL ; latt. cn nm GaN-hybrid VCSEL InGaN/GaN AlN/GaN DBR –Cracks/Leaks /p-doping & Ta 2 O 5 /SiO 2 dielectric DBR Ith=6.9 A (67 kA/cm 2 )pulse APL Lu et al, 92, (4/2008)

21 Projection system Structure of PQR Laser image chip TV Color recombination system Image chip

22

23 Matrix addressable scheme1. First etching 2. N-metal evaporation3. Second etching Perfect isolation ) 4. PI planarization & P-metal evaporation 5. Fully addressable PQR array ( Matrix addressable PQR array

24 PQR (Photonic Quantum Ring) laser Ultra-low threshold current ( ) dependent temperature stability High speed modulation : ~100MHz to GHz Speckle Free : 3-dim WCM (Whispering Cave Mode) Low power consumption PQR array Matrix addressable scheme Minimizing the chip size Lowering the number of connections Addressed through a row and column connection for the array : High count arrays [Matrix addressable] PQR laser chip TV


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