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12 Dec 2005

Volume 87, Issue 24, Articles (24xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 87, 243101 (2005); http://dx.doi.org/10.1063/1.2147713 (3 pages)

Y.-S. Choi, K. Hennessy, R. Sharma, E. Haberer, Y. Gao, S. P. DenBaars, S. Nakamura, E. L. Hu, and C. Meier
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Experimental and theoretical characterization of a lithium niobate photonic crystal

Matthieu Roussey, Maria-Pilar Bernal, Nadège Courjal, and Fadi I. Baida

Appl. Phys. Lett. 87, 241101 (2005); http://dx.doi.org/10.1063/1.2138348 (3 pages) | Cited 44 times

Online Publication Date: 5 December 2005

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In this letter, we investigate the feasibility of tunable lithium niobate (LiNbO3) photonic crystals. The optical response through a LiNbO3 photonic structure is theoretically determined in order to obtain a photonic band gap with optimal tunability. We show by means of a finite difference time domain simulation that the optimal lattice parameters can provide a Δλ = 7 nm shift in the photonic band gap for a Δn = 0.01 variation of the refractive index with an extinction ratio of −22.5 dB. The fabrication process and the optical characterization of these novel photonic crystal structures are also reported. The extinction ratio of the measured photonic band gap is lower than −12 dB.
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42.70.Qs Photonic bandgap materials
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
42.86.+b Optical workshop techniques

Coupling of PbS quantum dots to photonic crystal cavities at room temperature

Ilya Fushman, Dirk Englund, and Jelena Vučković

Appl. Phys. Lett. 87, 241102 (2005); http://dx.doi.org/10.1063/1.2138792 (3 pages) | Cited 35 times

Online Publication Date: 5 December 2005

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We demonstrate the coupling of PbS quantum dot emission to photonic crystal cavities at room temperature. The cavities are defined in 33% Al, AlGaAs membranes on top of oxidized AlAs. Quantum dots were dissolved in poly(methylmethacrylate) and spun on top of the cavities. Quantum dot emission is shown to map out the structure resonances. This technique may prove to be viable sources for room temperature cavity coupled single photon generation for quantum information processing applications. Moreover, our results also indicate that such commercially available quantum dots can be used for passive structure characterization. The deposition technique is versatile and allows layers with different dot densities and emission wavelengths to be redeposited on the same chip.
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42.70.Qs Photonic bandgap materials
68.65.Hb Quantum dots (patterned in quantum wells)

High-reflectance III-nitride distributed Bragg reflectors grown on Si substrates

M. A. Mastro, R. T. Holm, N. D. Bassim, C. R. Eddy, D. K. Gaskill, R. L. Henry, and M. E. Twigg

Appl. Phys. Lett. 87, 241103 (2005); http://dx.doi.org/10.1063/1.2140874 (3 pages) | Cited 14 times

Online Publication Date: 5 December 2005

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Distributed Bragg reflectors (DBRs) composed of an AlN/AlGaN superlattice were grown of Si (111) substrates. The first high-reflectance III-nitride DBR on Si was achieved by growing the DBR directly on the Si substrate to enhance the overall reflectance due to the high index of refraction contrast at the Si/AlN interface. For a 9× DBR, the measured peak reflectance of 96.8% actually exceeded the theoretical value of 96.1%. The AlN/AlGaN superlattice served the added purpose of compensating for the large tensile strain developed during the growth of a crack-free 500 nm GaN/7× DBR/Si structure. This achievement opens the possibility to manufacture high-quality III-nitride optoelectronic devices without optical absorption in the opaque Si substrate.
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42.79.Bh Lenses, prisms and mirrors
42.82.-m Integrated optics
68.65.Cd Superlattices
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Room-temperature operation of 3.26 μm GaSb-based type-I lasers with quinternary AlGaInAsSb barriers

M. Grau, C. Lin, O. Dier, C. Lauer, and M.-C. Amann

Appl. Phys. Lett. 87, 241104 (2005); http://dx.doi.org/10.1063/1.2140875 (3 pages) | Cited 59 times

Online Publication Date: 5 December 2005

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Quinternary AlGaInAsSb is introduced as a new barrier material for GaSb-based type-I laser diodes. For wavelengths beyond 3 μm, this material improves the valence-band offset between GaInAsSb quantum wells and barriers as compared to standard GaInAsSb/AlGaAsSb structures. The laser structures, which comprise three compressively strained GaInAsSb quantum wells and AlGaInAsSb barriers and waveguides, show good structural and optical quality. 3.26 μm emission has been achieved with ridge waveguide lasers working in pulsed operation up to 50 °C. With this emission wavelength, a strong absorption line of CH4 is accessible for gas absorption measurements.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)

Spatially periodic liquid crystal director field appearing in a photonic crystal template

Heinrich Matthias, Thorsten Röder, Ralf B. Wehrspohn, Heinz-S. Kitzerow, Sven Matthias, and Stephen J. Picken

Appl. Phys. Lett. 87, 241105 (2005); http://dx.doi.org/10.1063/1.2142100 (3 pages) | Cited 4 times

Online Publication Date: 6 December 2005

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Active tuning of photonic crystals can be achieved by filling the porous structures with liquid crystals. Here, the director field in macropores was studied by fluorescence confocal polarizing microscopy. For this purpose, the photonic crystal was infiltrated with a glass-forming liquid crystalline polymer, the sample was cooled below the glass transition temperature and, subsequently, the photonic crystal template was removed. Results on a structure with modulated pores indicate a spatially periodic director field containing a lattice of disclination rings.
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42.70.Qs Photonic bandgap materials
42.70.Df Liquid crystals
61.30.Vx Polymer liquid crystals
61.43.Gt Powders, porous materials

Surface plasmon dielectric waveguides

Igor I. Smolyaninov, Yu-Ju Hung, and Christopher C. Davis

Appl. Phys. Lett. 87, 241106 (2005); http://dx.doi.org/10.1063/1.2142096 (3 pages) | Cited 16 times

Online Publication Date: 6 December 2005

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We demonstrate that surface plasmon polaritons can be guided by nanometer-scale dielectric waveguides on top of a gold film. In a test experiment, plasmons were coupled to a curved 3 μm radius dielectric stripe, which was 200 nm wide and 138 nm thick, using a parabolic surface coupler. This experiment demonstrates that using surface plasmon polaritons the scale of optoelectronic devices based on dielectric waveguides can be shrunk by at least an order of magnitude.
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42.79.Gn Optical waveguides and couplers
85.60.-q Optoelectronic devices
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
71.36.+c Polaritons (including photon-phonon and photon-magnon interactions)

Anisotropic properties of ultrafast laser-driven microexplosions in lithium niobate crystal

Guangyong Zhou and Min Gu

Appl. Phys. Lett. 87, 241107 (2005); http://dx.doi.org/10.1063/1.2142083 (3 pages) | Cited 16 times

Online Publication Date: 6 December 2005

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Smooth voids are achieved in an anisotropic Fe:LiNbO3 crystal with a high refractive index by use of a femtosecond laser-driven microexplosion method. Due to the anisotropy of the crystal, the maximum fabrication depth and the fabrication power threshold are different in different crystal directions, indicating that the direction perpendicular to the crystal axis is more suitable for thick three-dimensional structure fabrication. The dependence of the threshold power on the illumination wavelength shows that the microexplosion mechanism is caused by a two-photon absorption process. As a result, a near threshold fabrication method can be used to generate quasispherical voids.
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42.70.Mp Nonlinear optical crystals
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
61.72.Qq Microscopic defects (voids, inclusions, etc.)
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.65.-k Nonlinear optics
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Tunable defect mode in a three-dimensional photonic crystal

G. Mertens, R. B. Wehrspohn, H.-S. Kitzerow, S. Matthias, C. Jamois, and U. Gösele

Appl. Phys. Lett. 87, 241108 (2005); http://dx.doi.org/10.1063/1.2139846 (3 pages) | Cited 20 times

Online Publication Date: 6 December 2005

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Three-dimensionally periodic structures made of macroporous silicon with varying pore diameter show a photonic stop band in the middle infrared spectral range. A discontinuity of the periodic pore width modulation forms a planar optical resonator with a corresponding transmission peak in the stop band. Infiltration of the porous structure with a nematic liquid crystal and subsequent temperature changing cause a spectral shift of the defect mode. The experimental observations are in good agreement with theoretical calculations.
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42.70.Qs Photonic bandgap materials
61.43.Gt Powders, porous materials
42.70.Df Liquid crystals
61.30.-v Liquid crystals

Highly directional emission via coupled surface-plasmon tunneling from electroluminescence in organic light-emitting devices

Jing Feng, Takayuki Okamoto, and Satoshi Kawata

Appl. Phys. Lett. 87, 241109 (2005); http://dx.doi.org/10.1063/1.2142085 (3 pages) | Cited 22 times

Online Publication Date: 6 December 2005

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We report that highly directional electroluminescence from top-emitting organic light-emitting devices (TEOLEDs) can be achieved by using a two-dimensionally periodically corrugated silver film as a cathode and an organic dye with a narrow bandwidth of emission spectrum as an emitting material. The resonant excitation of surface plasmons on the silver film interfaces contributes to the light transmission through the silver cathode and to the directional emission. The TEOLEDs with a europium complex as an emissive layer show beam divergence of less than 4° and the beam direction is controlled by periodicity of the corrugation.
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85.60.Jb Light-emitting devices

Second- and third-harmonic generation in birefringent photonic crystals and microcavities based on anisotropic porous silicon

I. V. Soboleva, E. M. Murchikova, A. A. Fedyanin, and O. A. Aktsipetrov

Appl. Phys. Lett. 87, 241110 (2005); http://dx.doi.org/10.1063/1.2133910 (3 pages) | Cited 11 times

Online Publication Date: 6 December 2005

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One-dimensional anisotropic photonic crystals and microcavities based on birefringent porous silicon are fabricated. The reflectance spectra demonstrate the presence of photonic band gap and microcavity modes with spectral positions tunable upon the sample azimuthal rotation around its normal and/or rotation of polarization plane of incident light. Simultaneous enhancement of second- and third-harmonic generation at the photonic band-gap edge due to the phase matching is observed. The angular positions of the second- and third-harmonic peaks are controllable via the anisotropy of the refractive indices of porous silicon layers.
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.70.Qs Photonic bandgap materials
78.20.Fm Birefringence

One-to-many laser fanout generated by single large-size two-dimensional holographic photonic crystal

Shou Liu, Xiangsu Zhang, Xiaoyun Chen, Ying Liu, and Xuechang Ren

Appl. Phys. Lett. 87, 241111 (2005); http://dx.doi.org/10.1063/1.2143133 (3 pages) | Cited 1 time

Online Publication Date: 7 December 2005

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The phenomenon of one-to-many laser fanout in large-size two-dimensional (2D) holographic photonic crystals (H-PhCs) is presented. Theoretical analysis demonstrates that the phenomenon is induced by multiple substrate waveguiding effect of 2D H-PhCs, and the orientations of the waveguided beams depend on the lattice structures of 2D H-PhCs. The fanout angle and separations between output spots are determined by λ/d, light incident angle and thickness of glass substrate, therefore can be controlled via fabricating special lattice structures. The phenomenon has the potential to enable the application of 2D PhCs as interconnection devices in optical networks.
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42.70.Qs Photonic bandgap materials
42.40.My Applications
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Organic pure-blue-light-emitting devices based on terfluorenes compounds

Yingfang Zhang, Gang Cheng, Yi Zhao, Jingying Hou, Shiyong Liu, Shi Tang, and Yuguang Ma

Appl. Phys. Lett. 87, 241112 (2005); http://dx.doi.org/10.1063/1.2141720 (3 pages) | Cited 13 times

Online Publication Date: 7 December 2005

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A series of organic pure-blue-light-emitting devices based on terflurorenes (TF) compounds are reported. In these double heterojunctions (DHJ) devices, two TF compounds act as a blue emitter, alternatively. Highly efficient pure-blue emissions are obtained from these devices. The maximum luminous efficiency of 1.52 cd/A (corresponding to an external quantum efficiency of 2.7%) with 1931 Commission International De L’Eclairage coordinates of (0.165, 0.072) is obtained. It is indicated that the DHJ device structure is beneficial to the performance of blue devices by means of effective confinement of excitons and carriers in the large energy gap blue emitter.
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85.60.Jb Light-emitting devices

Phase-matched second-harmonic generation at 1064 nm in quaternary crystals of silver thiogermanogallate

Valeriy Badikov, Galina Shevyrdyaeva, Vladimir Chizhikov, Vladimir Panyutin, Guibao Xu, Valentin Petrov, and Frank Noack

Appl. Phys. Lett. 87, 241113 (2005); http://dx.doi.org/10.1063/1.2141727 (3 pages) | Cited 1 time

Online Publication Date: 7 December 2005

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We demonstrate frequency doubling of 1064 nm radiation in sulphide crystals of AgxGaxGe1−xS2 having engineerable birefringence and superior nonlinearity in comparison to oxide crystals.
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.70.Mp Nonlinear optical crystals

Compact electrically pumped nitrogen-doped 4H-SiC terahertz emitters operating up to 150 K

P.-C. Lv, X. Zhang, J. Kolodzey, and A. Powell

Appl. Phys. Lett. 87, 241114 (2005); http://dx.doi.org/10.1063/1.2142294 (3 pages) | Cited 2 times

Online Publication Date: 7 December 2005

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We report a new type of electrically pumped THz source that emits at 9 THz with a maximum operating temperature of 150 K. The mechanism is based on dopant transitions in the 4H-SiC. The two nonequivalent donor sites of nitrogen in SiC were used to give the device a relatively high operating temperature and emission power. At a pumping current of 4.7 A at 4 K, the integrated spectral output power was 0.18 mWatt from the top surface with an area of 4 mm2. These results suggest that high-temperature operating THz devices can be fabricated from doped SiC.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Band gap tuning of InAs/InP quantum sticks using low-energy ion-implantation-induced intermixing

B. Salem, V. Aimez, D. Morris, A. Turala, P. Regreny, and M. Gendry

Appl. Phys. Lett. 87, 241115 (2005); http://dx.doi.org/10.1063/1.2142330 (3 pages) | Cited 12 times

Online Publication Date: 7 December 2005

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Low-energy (18 keV) phosphorus ion implantation and rapid thermal annealing at 650 °C for 120 s were used to create point defects and promote intermixing in InAs/InP quantum stick structures grown by molecular beam epitaxy. With these soft conditions for ion-implantation-induced intermixing, photoluminescence measurements at low temperature show a very large blueshift up to 350 nm and a narrow emission linewidth (down to 30 nm for ion dose equal to 5×1013 cm−2). The band gap tuning limit in this system was evaluated using implantation of phosphorus ions at various doses (1×1011–5×1014 cm−2), at a temperature of 200 °C followed by rapid thermal annealing.
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81.05.Ea III-V semiconductors
81.07.-b Nanoscale materials and structures: fabrication and characterization
78.67.-n Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures
78.55.Cr III-V semiconductors
73.20.At Surface states, band structure, electron density of states
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
61.72.uj III-V and II-VI semiconductors
61.72.Cc Kinetics of defect formation and annealing
61.72.J- Point defects and defect clusters

Tera-sample per second real-time waveform digitizer

Yan Han, Ozdal Boyraz, and Bahram Jalali

Appl. Phys. Lett. 87, 241116 (2005); http://dx.doi.org/10.1063/1.2142087 (3 pages) | Cited 12 times

Online Publication Date: 8 December 2005

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We demonstrate a real-time transient waveform digitizer with a record 1 tera-sample per second sampling rate. This is accomplished by using a photonic time stretch preprocessor which slows down the electrical waveform before it is captured by an electronic digitizer.
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07.68.+m Photography, photographic instruments; xerography

Room-temperature threshold reduction in vertical-cavity surface-emitting lasers by injection of spin-polarized electrons

J. Rudolph, S. Döhrmann, D. Hägele, M. Oestreich, and W. Stolz

Appl. Phys. Lett. 87, 241117 (2005); http://dx.doi.org/10.1063/1.2146064 (3 pages) | Cited 20 times

Online Publication Date: 8 December 2005

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We experimentally demonstrate the reduction of the laser threshold of a commercial GaAs/(AlGa)As vertical-cavity surface-emitting laser (VCSEL) by optical injection of spin-polarized electrons at room temperature. Calculations with a rate-equation model reproduce the measured reduction of 2.5% for injected electrons with 50% spin polarization. The model predicts an improved threshold reduction of 50% in otherwise identical VCSELs grown on a (110) substrate due to the enhanced spin lifetime in such structures.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Short pulse, high-repetition rate, passively Q-switched Er:yttrium-aluminum-garnet laser at 1.6 microns

Robert D. Stultz, Victor Leyva, and Kalin Spariosu

Appl. Phys. Lett. 87, 241118 (2005); http://dx.doi.org/10.1063/1.2142086 (2 pages) | Cited 11 times

Online Publication Date: 9 December 2005

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We have demonstrated a continuously pumped, passively Q-switched, 1617 nm Er:yttrium-aluminum-garnet (YAG) laser oscillator with a pulse width of just under 7 ns, a pulse repetition frequency of about 4 kHz, and an output power of 0.9 W. The oscillator was pumped using an Er:fiber laser at 1534 nm, and Q switched using a Cr2+:ZnSe saturable absorber. The Er:YAG laser is useful either stand-alone, or as the master oscillator in a master-oscillator-power-amplifier architecture.
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42.55.Rz Doped-insulator lasers and other solid state lasers
42.60.By Design of specific laser systems
42.55.Px Semiconductor lasers; laser diodes
42.65.Re Ultrafast processes; optical pulse generation and pulse compression

Coupled-resonator optical waveguides for biochemical sensing of nanoliter volumes of analyte in the terahertz region

Hamza Kurt and D. S. Citrin

Appl. Phys. Lett. 87, 241119 (2005); http://dx.doi.org/10.1063/1.2140479 (3 pages) | Cited 21 times

Online Publication Date: 9 December 2005

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We present a detailed study of coupled-resonator optical waveguide (CROW) based sensors for biochemical sensing. The sensitivity dependence on the CROW structure parameters, such as intercavity distance and cavity type, is investigated for the effects in the THz region of the EM spectrum of introducing small quantities of molecules, such as DNA, in the holes. Introducing the absorptive material into the low-index medium greatly affects the shape of the propagating modes of the CROW and the transmitted E-field. The shift of the resonant frequency also depends linearly on the refractive index changes for off-resonant case (dispersive effect).
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87.80.-y Biophysical techniques (research methods)
87.15.N- Properties of solutions of macromolecules
42.79.Gn Optical waveguides and couplers
82.80.-d Chemical analysis and related physical methods of analysis
02.70.Bf Finite-difference methods
87.14.G- Nucleic acids
87.15.M- Spectra of biomolecules
42.70.Qs Photonic bandgap materials
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
84.40.-x Radiowave and microwave (including millimeter wave) technology

Coupled islands of photonic crystal heterostructures implemented with vertical-cavity surface-emitting lasers

L. D. A. Lundeberg, D. L. Boiko, and E. Kapon

Appl. Phys. Lett. 87, 241120 (2005); http://dx.doi.org/10.1063/1.2147728 (3 pages) | Cited 12 times

Online Publication Date: 9 December 2005

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Formation of bonding and antibonding states of two coupled photonic crystal heterostructure islands implemented with arrays of vertical-cavity surface-emitting lasers is studied theoretically and experimentally. Coupling of the photonic envelope wave functions confined to each island is brought about by tunneling across the heterobarrier separating the islands. Numerical simulations predict the bonding state to have the lowest modal losses. The experimental observations of lasing supermodes confirm this prediction, showing the island coupling in the bonding state of the coupled envelope functions.
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42.55.Px Semiconductor lasers; laser diodes
42.70.Qs Photonic bandgap materials
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Effective connecting architecture for tandem organic light-emitting devices

Chieh-Wei Chen, Yin-Jui Lu, Chung-Chih Wu, Elbert Hsing-En Wu, Chih-Wei Chu, and Yang Yang

Appl. Phys. Lett. 87, 241121 (2005); http://dx.doi.org/10.1063/1.2141718 (3 pages) | Cited 75 times

Online Publication Date: 9 December 2005

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An effective connecting structure for tandem organic light-emitting devices is reported. The connecting structure consists of a thin metal layer as the common electrode, a hole-injection layer containing MoO3 on one side of the common electrode, and an electron-injection layer involving Cs2CO3 on the other side. Such a connecting structure permits efficient opposite hole and electron injection into two adjacent emitting units and gives tandem devices superior electrical and optical performances. Furthermore, the present connecting structure involves no sputtering or handling of reactive metals during device fabrication and can be prepared purely by thermal evaporation, thus rendering device processing more feasible.
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85.60.Jb Light-emitting devices
81.20.Vj Joining; welding

Thin ordered bundles of infrared-transmitting silver halide fibers

Yaron Lavi, Arnon Millo, and Abraham Katzir

Appl. Phys. Lett. 87, 241122 (2005); http://dx.doi.org/10.1063/1.2141728 (3 pages) | Cited 5 times

Online Publication Date: 9 December 2005

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Thin, ordered bundles of fibers were extruded from AgClxBr1−x (0<x<1) crystals. They consisted of 100 individual fibers of average diameters 30–45 μm, packed in tight arrays to form bundles of outer diameters 0.7–2.0 mm. The bundles transmitted radiation in the spectral range of 3–20 μm and exhibited relatively low transmission losses and no bending losses. The bundles were used to transmit thermal images of objects at room temperature to a distance of several meters. These thin and flexible bundles will be useful for fiber-optic thermal imaging in medical and industrial applications.
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42.81.Wg Other fiber-optical devices
42.81.Bm Fabrication, cladding, and splicing
42.81.Cn Fiber testing and measurement of fiber parameters
42.79.Pw Imaging detectors and sensors
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors

Avalanche multiplication in AlGaN based solar-blind photodetectors

R. McClintock, A. Yasan, K. Minder, P. Kung, and M. Razeghi

Appl. Phys. Lett. 87, 241123 (2005); http://dx.doi.org/10.1063/1.2140610 (3 pages) | Cited 16 times

Online Publication Date: 9 December 2005

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Avalanche multiplication has been observed in solar-blind AlGaN-based p-i-n photodiodes. Upon ultraviolet illumination, the optical gain shows a soft breakdown starting at relatively low electric fields, eventually saturating without showing a Geiger mode breakdown. The devices achieve a maximum optical gain of 700 at a reverse bias of 60 V. By modeling the device, it is found that this corresponds to an electric-field strength of 1.7 MV/cm.
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85.60.Gz Photodetectors (including infrared and CCD detectors)
85.60.Dw Photodiodes; phototransistors; photoresistors
61.82.Fk Semiconductors

Lasing in interferometrically structured organic materials

Rik Harbers, John A. Hoffnagle, William D. Hinsberg, Rainer F. Mahrt, Nikolaj Moll, Daniel Erni, and Werner Bächtold

Appl. Phys. Lett. 87, 241124 (2005); http://dx.doi.org/10.1063/1.2146210 (3 pages) | Cited 2 times

Online Publication Date: 9 December 2005

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We present feedback structures for an organic-photonic-crystal laser created by directly structuring the gain medium, consisting of UVII-HS resist doped with a mixture of the laser dyes Coumarin and DCM. The photonic-crystal structure is realized by means of interference lithography. This approach greatly reduces the number of steps required to realize the feedback structure of an organic laser. The dispersion relations obtained expermimentally agree very well with the computer simulated band diagram.
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42.55.Tv Photonic crystal lasers and coherent effects
42.70.Qs Photonic bandgap materials
42.70.Hj Laser materials
42.70.Jk Polymers and organics
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Light emission of metal halide lamps under micro- and hypergravity conditions

W. W. Stoffels, P. C. M. Kemps, J. Beckers, G. M. W. Kroesen, and M. Haverlag

Appl. Phys. Lett. 87, 241501 (2005); http://dx.doi.org/10.1063/1.2137989 (3 pages) | Cited 8 times

Online Publication Date: 5 December 2005

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The wavelength-integrated light output from a metal halide discharge lamp is measured for gravity conditions varying from 0 to 1.8 g during parabolic flights. The results show that the changing gravity affects the convection flow in the lamp, which in turn changes the total light output. For vertically burning lamps, the sign and magnitude of the effect can be predicted using the demixing parameter: the ratio of typical diffusion to convection times. In horizontally burning lamps at 0 g, the absence of convective mixing results in a reduced light emission.
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52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.25.Fi Transport properties
52.30.-q Plasma dynamics and flow
52.80.Mg Arcs; sparks; lightning; atmospheric electricity
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