APL: Lasers, Optics, and Optoelectronics http://scitation.aip.org/ APL: Lasers, Optics, and Optoelectronics Demonstration of enhanced absorption in thin film Si solar cells with textured photonic crystal back reflector http://link.aip.org/link/?APL/93/221105/1&agg=rss L. Zeng, P. Bermel, Y. Yi, B. A. Alamariu, K. A. Broderick et al.<br/> Herein the authors report the experimental application of a powerful light trapping scheme, the textured photonic crystal (TPC) backside reflector, to thin film Si solar cells. TPC combines a one-dimensional photonic crystal as a distributed Bragg reflector with a diffraction grating. Light absorpti ... [Appl. Phys. Lett. 93, 221105 (2008)] published Mon Dec 1, 2008. Twisted liquid crystal pi cell stabilized by polymer-sustained alignment http://link.aip.org/link/?APL/93/221103/1&agg=rss Tien-Jung Chen, Yuan-Hsin Cheng, and Sheng-Ming Wu<br/> A uniform pi-twist liquid crystal (LC) alignment was stabilized in a pi cell by photopolymerization of a minute amount of monomers without using any chiral material. Controlling UV exposure time can vary the LC pretilt angle to achieve a stabilized pi-twist state. This type of pi-twisted LC cell mad ... [Appl. Phys. Lett. 93, 221103 (2008)] published Mon Dec 1, 2008. Ultrahigh-brightness 850 nm GaAs/AlGaAs photonic crystal laser diodes http://link.aip.org/link/?APL/93/221102/1&agg=rss K. Posilovic, T. Kettler, V. A. Shchukin, N. N. Ledentsov, U. W. Pohl et al.<br/> One-dimensional photonic crystal lasers emitting in the 850 nm range show high internal quantum efficiencies of 93% and very narrow vertical beam divergence of 7.1 degrees (full width at half maximum). 50 [mu]m broad area lasers with unpassivated facets exhibit a high total output power of nearly ... [Appl. Phys. Lett. 93, 221102 (2008)] published Mon Dec 1, 2008. GaN nanostructured p-i-n photodiodes http://link.aip.org/link/?APL/93/221104/1&agg=rss J. L. Pau, C. Bayram, P. Giedraitis, R. McClintock, and M. Razeghi<br/> We report the fabrication of nanostructured p-i-n photodiodes based on GaN. Each device comprises arrays of ~200 nm diameter and 520 nm tall nanopillars on a 1 [mu]m period, fabricated by e-beam lithography. Strong rectifying behavior was obtained with an average reverse current per nanopillar of ... [Appl. Phys. Lett. 93, 221104 (2008)] published Mon Dec 1, 2008. Enhanced linearly polarized lasing emission from nanoimprinted surface-emitting distributed feedback laser based on polymeric liquid crystals http://link.aip.org/link/?APL/93/221101/1&agg=rss Soon Moon Jeong, Na Young Ha, Mu Guen Chee, Fumito Araoka, Ken Ishikawa et al.<br/> The authors have demonstrated the enhancement of linearly polarized lasing emission intensity using a structure made by a simple fabrication process. The enhanced lasing is achieved using a nanoimprinted distributed feedback structure together with spin-coated polymeric liquid crystals. The backward ... [Appl. Phys. Lett. 93, 221101 (2008)] published Mon Dec 1, 2008. High quantum efficiency back-illuminated GaN avalanche photodiodes http://link.aip.org/link/?APL/93/211107/1&agg=rss C. Bayram, J. L. Pau, R. McClintock, M. Razeghi, M. P. Ulmer et al.<br/> Back-illuminated avalanche photodiodes (APDs) composed of heterojunctions of either p-GaN/i-GaN/n-AlGaN or p-GaN/i-GaN/n-GaN/n-AlGaN were fabricated on AlN templates. At low voltage, an external quantum efficiency of 57% at 352 nm with a bandpass response was achieved by using AlGaN in the n-layer. ... [Appl. Phys. Lett. 93, 211107 (2008)] published Wed Nov 26, 2008. Single mode emitting ridge waveguide quantum cascade lasers coupled to an active ring resonator filter http://link.aip.org/link/?APL/93/211106/1&agg=rss Julia Semmel, Wolfgang Kaiser, Holger Hofmann, Sven Hofling, and Alfred Forchel<br/> Quantum cascade ridge waveguide lasers with coupled ring resonators have been fabricated. Coupling of an actively pumped microring resonator to a ridge waveguide device allows for filtering the numerous FabryPerot modes emerging in the ridge waveguide. Due to the large free spectral range of the rin ... [Appl. Phys. Lett. 93, 211106 (2008)] published Wed Nov 26, 2008. Theory of exciton-polariton lasing at room temperature in ZnO microcavities http://link.aip.org/link/?APL/93/211105/1&agg=rss R. Johne, D. D. Solnyshkov, and G. Malpuech<br/> We use the semiclassical Boltzmann equations to describe the exciton-polariton relaxation in a bulk ZnO microcavity at room temperature. We present kinetic phase diagrams which report the lasing threshold versus the main sample parameters, such as the polariton lifetime or the value of the Rabi spli ... [Appl. Phys. Lett. 93, 211105 (2008)] published Wed Nov 26, 2008. High order mode oscillation in a terahertz photonic-band-gap multibeam reflex klystron http://link.aip.org/link/?APL/93/211104/1&agg=rss Kyu-Ha Jang, Seok-Gy Jeon, Jung-Il Kim, Jong-Hyo Won, Jin-Kyu So et al.<br/> TM-like higher order mode was excited in a multibeam reflex klystron oscillator employing a hybrid photonic-band-gap (PBG) cavity using a three-dimensional particle-in-cell simulation. One side of a conventional metal cavity was replaced with a dielectric photonic crystal lattice to form a hybrid PB ... [Appl. Phys. Lett. 93, 211104 (2008)] published Tue Nov 25, 2008. Polarization-selective resonant photonic crystal photodetector http://link.aip.org/link/?APL/93/211103/1&agg=rss Jin-Kyu Yang, Min-Kyo Seo, In-Kag Hwang, Sung-Bock Kim, and Yong-Hee Lee<br/> Resonance-assisted photonic crystal (PhC) slab photodetectors are demonstrated by utilizing six 7-nm-thick InGaAsP quantum wells. In order to encourage efficient photon coupling into the slab from the vertical direction, a coupled-dipole-cavity-array PhC structure is employed. Inheriting the charact ... [Appl. Phys. Lett. 93, 211103 (2008)] published Tue Nov 25, 2008. Narrow-line coherently combined tapered laser diodes in a Talbot external cavity with a volume Bragg grating http://link.aip.org/link/?APL/93/211102/1&agg=rss David Paboeuf, Gaelle Lucas-Leclin, Patrick Georges, Nicolas Michel, Michel Krakowski et al.<br/> We present the phase locking of an array of index-guided tapered laser diodes. An external cavity based on the self-imaging Talbot effect has been built. A volume Bragg grating is used as the output coupler to stabilize and narrow the spectrum at 976 nm. A power of 1.7 W is achieved in the in-phas ... [Appl. Phys. Lett. 93, 211102 (2008)] published Tue Nov 25, 2008. Carrier concentration dependence of terahertz transmission on conducting ZnO films http://link.aip.org/link/?APL/93/211101/1&agg=rss Guohong Ma, Dong Li, Hong Ma, Jie Shen, Chenguo Wu et al.<br/> With the dc reactive magnetron sputtering method, conducting ZnO thin films with different carrier concentrations on glass substrate were fabricated. The dielectric responses of the ZnO films are characterized with terahertz time-domain spectroscopy. Frequency-dependent conductivity, power absorptio ... [Appl. Phys. Lett. 93, 211101 (2008)] published Mon Nov 24, 2008. Ponderomotive electron acceleration by polarization-gated surface-enhanced optical fields http://link.aip.org/link/?APL/93/201108/1&agg=rss Peifen Lu, Jian Wu, Hongxing Qi, and Heping Zeng<br/> We study ponderomotive electron acceleration with polarization-gated surface-plasmon-resonance enhanced optical fields excited by two counter-incident femtosecond laser pulses. Such a polarization-gated excitation scheme creates an intense linearly polarized high-gradient evanescent field for electr ... [Appl. Phys. Lett. 93, 201108 (2008)] published Fri Nov 21, 2008. Phonon-assisted ultraviolet anti-Stokes photoluminescence from GaN film grown on Si (111) substrate http://link.aip.org/link/?APL/93/201107/1&agg=rss Suvranta K. Tripathy, Guibao Xu, Xiaodong Mu, Yujie J. Ding, Muhammad Jamil et al.<br/> Phonon-assisted anti-Stokes photoluminescence (ASPL) in the ultraviolet region has been observed in the GaN film grown on a Si (111) substrate. The ASPL peaks are observable only at sufficiently low temperatures. In addition, even if the photon energy is [approximate]318 meV below the transition en ... [Appl. Phys. Lett. 93, 201107 (2008)] published Thu Nov 20, 2008. Experimental demonstration of tunable negative phase velocity and negative refraction in a ferromagnetic/ferroelectric composite metamaterial http://link.aip.org/link/?APL/93/201106/1&agg=rss Hongjie Zhao, Lei Kang, Ji Zhou, Qian Zhao, Longtu Li et al.<br/> A tunable left-handed transmission is demonstrated experimentally in a ferromagnetic/ferroelectric composite metamaterial (CMM) consisting of an array of yttrium iron garnet (YIG) rods combined with barium strontium titanate (BST) rods. We observed a passband in the CMM within the overlap of the sto ... [Appl. Phys. Lett. 93, 201106 (2008)] published Thu Nov 20, 2008. Multiple pulse thermal damage thresholds of materials for x-ray free electron laser optics investigated with an ultraviolet laser http://link.aip.org/link/?APL/93/201105/1&agg=rss Stefan P. Hau-Riege, Richard A. London, Richard M. Bionta, Regina Soufli, Dmitri Ryutov et al.<br/> Optical elements to be used for x-ray free electron lasers (XFELs) must withstand multiple high-fluence pulses. We have used an ultraviolet laser to study the damage of two candidate materials, crystalline Si and BC-coated Si, emulating the temperature profile expected to occur in optics exposed to ... [Appl. Phys. Lett. 93, 201105 (2008)] published Wed Nov 19, 2008. Strain-induced low dimensional confinement structures http://link.aip.org/link/?APL/93/201104/1&agg=rss Nadir Sekkal and V. R. Velasco<br/> We propose here confinement structures similar to heterostructures and superlattices. The present structures can be obtained by applying strain to a single material in a periodic or aperiodic way. The conversion of an indirect gap into an optical active direct or quasidirect gap problem has also bee ... [Appl. Phys. Lett. 93, 201104 (2008)] published Tue Nov 18, 2008. Coherent anti-Stokes Raman microspectroscopy using spectral focusing with glass dispersion http://link.aip.org/link/?APL/93/201103/1&agg=rss Israel Rocha-Mendoza, Wolfgang Langbein, and Paola Borri<br/> We demonstrate experimentally that coherent anti-Stokes Raman microspectroscopy with high spectral resolution is achieved using femtosecond laser pulses chirped up to a few picoseconds by glass elements of known group-velocity dispersion without significant intensity losses. By simply choosing the l ... [Appl. Phys. Lett. 93, 201103 (2008)] published Tue Nov 18, 2008. Compensation of thermal refraction effect in high-Q toroidal microresonator by polydimethylsiloxane coating http://link.aip.org/link/?APL/93/201102/1&agg=rss L. He, Y.-F. Xiao, C. Dong, J. Zhu, V. Gaddam et al.<br/> We experimentally and theoretically characterize the thermal refraction effect in a silica microtoroid and demonstrate that such effect can be reduced or even eliminated by applying a thin layer of polydimethylsiloxane (PDMS) to the surface of the silica resonator. By increasing the coating thicknes ... [Appl. Phys. Lett. 93, 201102 (2008)] published Mon Nov 17, 2008. Converging and wave guiding of Gaussian beam by two-layer dielectric rods http://link.aip.org/link/?APL/93/201101/1&agg=rss W. Dai and C. M. Soukoulis<br/> We have shown that a two-layer dielectric structure can give excellent beaming and enhanced transmission simultaneously of a Gaussian source. The front surface of the layer of dielectric rods supports surface states and the rear grading layer couples the surface states to radiation modes. By repeati ... [Appl. Phys. Lett. 93, 201101 (2008)] published Mon Nov 17, 2008. Transformable broad-band transparency and amplification in negative-index films http://link.aip.org/link/?APL/93/191117/1&agg=rss Alexander K. Popov and Sergey A. Myslivets<br/> The possibility to produce laser-induced optical transparency of a metamaterial slab through the entire negative-index frequency domain is shown above a certain control laser field intensity threshold. ... [Appl. Phys. Lett. 93, 191117 (2008)] published Fri Nov 14, 2008.