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30 Sep 2002

Volume 81, Issue 14, pp. 2493-2662

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Colloidal photonic crystal microchannel array with periodically modulated thickness

H. Míguez, S. M. Yang, and G. A. Ozin

Appl. Phys. Lett. 81, 2493 (2002); http://dx.doi.org/10.1063/1.1510959 (3 pages) | Cited 9 times

Online Publication Date: 23 September 2002

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Here we report on the optical properties of a micrometer scale array of periodically modulated thickness colloidal crystals. A combination of soft-lithography, micromolding, and microfluidics techniques is employed to form rectangular microchannels that can impose a periodic modulation of the thickness of colloidal crystals grown within them. Correspondingly, a periodic fluctuation of the photonic band structure occurs at distances of the order of a few microns. Experimental evidence of this effect is obtained by optical microspectroscopy. Results are analyzed in terms of finite crystal size theoretical calculations. © 2002 American Institute of Physics.
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42.70.Qs Photonic bandgap materials
42.82.Cr Fabrication techniques; lithography, pattern transfer
82.70.Dd Colloids
81.10.Fq Growth from melts; zone melting and refining
47.85.Np Fluidics
42.86.+b Optical workshop techniques

All-optical cw laser polarization conversion at 1.55 μm by two-beam coupling in nematic liquid crystal films

I. C. Khoo and J. Ding

Appl. Phys. Lett. 81, 2496 (2002); http://dx.doi.org/10.1063/1.1510965 (3 pages) | Cited 13 times

Online Publication Date: 23 September 2002

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We have demonstrated efficient all-optical polarization conversion of cw 1.55 μm laser in nematic liquid crystal films. The process is mediated by coherent two-beam coupling effect between an incident polarized laser and its orthogonally polarized noise component scattered by the director axis fluctuations. We report here a quantitative theory that accounts for severe pump depletion and high-efficiency polarization conversion and demonstrate good agreement with experimental observations. © 2002 American Institute of Physics.
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42.70.Df Liquid crystals
42.25.Ja Polarization
42.25.Lc Birefringence
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation

Two-dimensional photonic crystal hexagonal waveguide ring laser

Se-Heon Kim, Han-Youl Ryu, Hong-Gyu Park, Guk-Hyun Kim, Yong-Seok Choi, Yong-Hee Lee, and Jeong-Soo Kim

Appl. Phys. Lett. 81, 2499 (2002); http://dx.doi.org/10.1063/1.1510583 (3 pages) | Cited 38 times

Online Publication Date: 23 September 2002

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Hexagonal ring-type resonators defined by two-dimensional photonic crystal waveguides are proposed and demonstrated. Lasing actions are observed from the photonic crystal ring resonator patterned on a free-standing slab with InGaAsP active layers emitting near 1.55 μm. For a ring resonator with 8-μm diameter, the threshold peak pump power is ∼3 mW. The quality factor of the ring resonator mode estimated from below-threshold linewidth shows that the sum of the propagation loss and the bending loss of the photonic crystal ring resonator is less than ∼ 260 cm−1. The photonic crystal ring resonators can be used for the characterization of the optical losses in photonic crystal waveguides. © 2002 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.70.Qs Photonic bandgap materials
42.60.By Design of specific laser systems

Wavelength tunable ultrashort pulse generation from a passively mode-locked asymmetric-quantum-well semiconductor laser

M. J. Brennan, J. N. Milgram, P. Mascher, and H. K. Haugen

Appl. Phys. Lett. 81, 2502 (2002); http://dx.doi.org/10.1063/1.1510587 (3 pages) | Cited 2 times

Online Publication Date: 23 September 2002

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Optical pulses are generated from a passively mode-locked dual asymmetric-quantum-well semiconductor laser mounted in a linear external cavity. The devices are fabricated with two sections, one of which contains a bend in the waveguide for external cavity coupling. Pulses 2.0–3.9 ps in duration have been generated, which are tunable over 61 nm, from 954 to 1015 nm. Pulse compression yields durations as short as 470 fs with peak powers as high as 1.5 W. © 2002 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.60.Fc Modulation, tuning, and mode locking
42.65.Re Ultrafast processes; optical pulse generation and pulse compression

InGaAsP/InP avalanche photodiodes for photon counting at 1.06 μm

K. A. McIntosh, J. P. Donnelly, D. C. Oakley, A. Napoleone, S. D. Calawa, L. J. Mahoney, K. M. Molvar, E. K. Duerr, S. H. Groves, and D. C. Shaver

Appl. Phys. Lett. 81, 2505 (2002); http://dx.doi.org/10.1063/1.1509469 (3 pages) | Cited 26 times

Online Publication Date: 23 September 2002

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Geiger-mode (photon-counting) operation at 1.06 μm has been demonstrated with InGaAsP/InP avalanche photodiodes operated at room temperature. A photon detection efficiency of 33% was measured on uncoated detectors, representing an internal avalanche probability of 60%. Under identical bias conditions a dark count rate as low as 1.7 MHz was measured at 290 K, consistent with a primary dark current of <0.3 pA. Dark count rates drop by approximately 50–200× by cooling the detectors to 210 K (−63 °C). © 2002 American Institute of Physics.
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85.60.Dw Photodiodes; phototransistors; photoresistors
85.60.Gz Photodetectors (including infrared and CCD detectors)
73.61.Ey III-V semiconductors
72.40.+w Photoconduction and photovoltaic effects

1 mW AlInGaN-based ultraviolet light-emitting diode with an emission wavelength of 348 nm grown on sapphire substrate

T. Wang, Y. H. Liu, Y. B. Lee, J. P. Ao, J. Bai, and S. Sakai

Appl. Phys. Lett. 81, 2508 (2002); http://dx.doi.org/10.1063/1.1510967 (3 pages) | Cited 42 times

Online Publication Date: 23 September 2002

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By introducing the AlInGaN/AlGaN quaternary system as an active region, we fabricated an UV light-emitting diode (LED) with an emission wavelength of 348 nm. The optical power is 1 mW at an injection current of 50 mA under a bare-chip geometry, which is the highest report among UV–LEDs with an emission wavelength of around 350 nm grown on sapphire substrate. It means that the optical power of such LEDs is high enough to be used in practical application. In contrast to it, a similar UV–LED based on GaN/AlGaN system as an active region has been also grown, whose optical power is less than that of the AlInGaN/AlGaN-based UV–LED by one order of magnitude. The temperature-dependent photoluminescence study indicates that there exists a strong exciton-localization effect in the AlInGaN/AlGaN material system, while there is no distinguished exciton-localization effect in the GaN/AlGaN material system. Therefore, the high performance of the AlInGaN/AlGaN-based UV–LED can be attributed to the enhanced exciton-localization effect. © 2002 American Institute of Physics.
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85.60.Jb Light-emitting devices
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors

Random lasing following two-photon excitation of highly scattering gain media

Giannis Zacharakis, Nektarios A. Papadogiannis, and Theodore G. Papazoglou

Appl. Phys. Lett. 81, 2511 (2002); http://dx.doi.org/10.1063/1.1511284 (3 pages) | Cited 16 times

Online Publication Date: 23 September 2002

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We present experimental evidence of laser emission following two-photon excitation of dye-infiltrated random gain media with optical properties similar to biological tissue. The excitation was performed with femtosecond laser pulses at 800 nm and the emission (at 480 nm) was recorded with a spectrograph streak camera system. The coherent properties of the random lasing emission were also investigated by performing single photon counting. The applications of coherent laser light that can be emitted deep inside a random medium are far reaching, particularly for imaging and therapeutic purposes. © 2002 American Institute of Physics.
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42.55.Mv Dye lasers
42.55.Rz Doped-insulator lasers and other solid state lasers
42.62.Be Biological and medical applications
87.63.L- Visual imaging
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.50.Ar Photon statistics and coherence theory
42.25.Fx Diffraction and scattering
42.25.Dd Wave propagation in random media

Demonstration and optical characteristics of electro-optic Bragg modulators in periodically poled lithium niobate in the near-infrared

J. A. Abernethy, C. B. E. Gawith, R. W. Eason, and P. G. R. Smith

Appl. Phys. Lett. 81, 2514 (2002); http://dx.doi.org/10.1063/1.1510964 (3 pages) | Cited 23 times

Online Publication Date: 23 September 2002

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We report the infrared operation of a bulk optical Bragg modulator based on electro-optically induced refractive index gratings in z-cut periodically poled lithium niobate. Efficiencies in the first order of 45% for 1064 nm e-polarized light and 30% for o-polarized light were achieved, with maximum on/off ratios of 15:1 and 9:1, respectively. Field-induced light scattering effects due to poling are observed at higher drive voltages and compromised device performance due to these scattering effects is predicted to limit long-wavelength operation of these devices. © 2002 American Institute of Physics.
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42.79.Hp Optical processors, correlators, and modulators
42.79.Dj Gratings

Improved transmission characteristics of moderate refractive index contrast photonic crystal slabs

G. Böttger, C. Liguda, M. Schmidt, and M. Eich

Appl. Phys. Lett. 81, 2517 (2002); http://dx.doi.org/10.1063/1.1511816 (3 pages) | Cited 16 times

Online Publication Date: 23 September 2002

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Finite two-dimensional (2D)-photonic crystal slab waveguide structures from moderate refractive index materials have been investigated theoretically and results were compared with experimental data. 3D-finite difference time domain (3D-FDTD) simulations reveal a strong dependence of the transmission on the etching depth. For structures with etching depths less than the waveguide core thickness, both a substantial leakage of optical power to the substrate and a spatial mismatch of the transmitted field to the waveguide mode were found, leading to unsatisfactory transmissions. These losses occur mainly on the airband side of the spectrum where the optical field is concentrated in the holes. However, hole depths extending into the substrate by only 0.5 μm lead to an almost perfect mode match at transmission values exceeding 90%. © 2002 American Institute of Physics.
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42.79.Gn Optical waveguides and couplers
42.70.Qs Photonic bandgap materials
02.70.Bf Finite-difference methods

Submicron extreme ultraviolet imaging using high-harmonic radiation

Marek Wieland, Rolf Frueke, Thomas Wilhein, Christian Spielmann, Martin Pohl, and Ulf Kleineberg

Appl. Phys. Lett. 81, 2520 (2002); http://dx.doi.org/10.1063/1.1511288 (3 pages) | Cited 18 times

Online Publication Date: 23 September 2002

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We report on experiments using high-harmonic (HH) radiation for microscopy imaging at 13 nm wavelength. A simple setup using a zone plate as objective and a back-illuminated CCD as detector yields at moderate magnifications of M ≈ 60 a spatial resolution of δx<0.8 μm demonstrated with a sample of mica. The HH radiation was monochromatized by means of a high-efficiency multilayer monochromator consisting of two Mo/Si-mirros. © 2002 American Institute of Physics.
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07.60.Pb Conventional optical microscopes
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.79.Bh Lenses, prisms and mirrors
41.85.Si Particle beam collimators, monochromators
42.79.Nv Optical frequency converters

Low-threshold-current-density 1300-nm dilute-nitride quantum well lasers

Nelson Tansu, Nicholas J. Kirsch, and Luke J. Mawst

Appl. Phys. Lett. 81, 2523 (2002); http://dx.doi.org/10.1063/1.1511290 (3 pages) | Cited 80 times

Online Publication Date: 23 September 2002

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Metalorganic chemical vapor deposition-grown In0.4Ga0.6As0.995N0.005 quantum well (QW) lasers have been realized, at an emission wavelength of 1.295 μm, with threshold and transparency current densities as low as 211 A/cm2 (for L=2000 μm) and 75 A/cm2, respectively. The utilization of a tensile-strained GaAs0.67P0.33 buffer layer and GaAs0.85P0.15 barrier layers allows a highly-compressively-strained In0.4Ga0.6As0.995N0.005 QW to be grown on a high-Al-content lower cladding layer, resulting in devices with high current injection efficiency (ηinj ∼ 97%). © 2002 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
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