Optics news

Simultaneous wavenumber measurement and coherence detection using temporal phase unwrapping

Applied Optics - 0 sec ago
A. Davila, J. M. Huntley, C. Pallikarakis, P. D. Ruiz, J. M. Coupland
Wavelength scanning interferometry and swept-source optical coherence tomography require accurate measurement of time-varying laser wavenumber changes. We describe here a method based on recording interferograms of multiple wedges to provide simultaneously high wavenumber resolution and immunity to ... [Appl. Opt. 51, 558-567 (2012)]
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Quantitative carbon measurement in anthracite using laser-induced breakdown spectroscopy with binder

Applied Optics - 0 sec ago
Tingbi Yuan, Zhe Wang, Lizhi Li, Zongyu Hou, Zheng Li, Weidou Ni
Quantitative carbon measurement in anthracites remains difficult with laser-induced breakdown spectroscopy (LIBS) due to its relatively high measurement uncertainty. To improve the measurement repeatability, binders to bind the anthracite powder together were utilized for LIBS measurement. Results ... [Appl. Opt. 51, B22-B29 (2012)]
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Electrically pumped simultaneous ultraviolet and visible random laser actions from ZnO-CdO interdiffused film

Ye Tian, Xiangyang Ma, Luelue Xiang, and Deren Yang
We have demonstrated electrically pumped simultaneous ultraviolet (UV) and visible random laser (RL) actions from ZnO-CdO interdiffused film. The interdiffusion between ZnO and CdO films at 700 degrees C forms composition-graded CdZnO alloy within the ZnO-CdO interdiffused film, which is luminescen ... [Appl. Phys. Lett. 99, 261111 (2011)] published Fri Dec 30, 2011.
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Whispering gallery modes with different polarizations in semiconductor microrod with rectangle shape

Xiaoliang Ye, Huibing Mao, Jiqing Wang, and Ziqiang Zhu
The whispering gallery modes (WGMs) of the ZnO photoluminescence emission were investigated in this paper. The transmission electron microscopy and X-ray diffraction results confirm that the rectangle microrod has a single crystalline wurtzite structure. Except for the band-edge emission, the visibl ... [Appl. Phys. Lett. 99, 261112 (2011)] published Fri Dec 30, 2011.
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Lasing in planar semiconductor diodes

Giorgio De Simoni, Lukas Mahler, Vincenzo Piazza, Alessandro Tredicucci, Christine A. Nicoll et al.
We present a planar laser diode based on a simple fabrication scheme compatible with virtually any geometry accessible by standard semiconductor lithography technique. We show that our lasers exhibit ~1 GHz -3 dB-modulation-bandwidth already in this prototypical implementation. Directions for a sign ... [Appl. Phys. Lett. 99, 261110 (2011)] published Fri Dec 30, 2011.
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Performance of large-area few-layer graphene saturable absorber in femtosecond bulk laser

Jin-Long Xu, Xian-Lei Li, Jing-Liang He, Xiao-Peng Hao, Yong-Zhong Wu et al.
Using large-area graphene sheets of 1-10 layers prepared by the improved liquid phase exfoliation technique, the mode locking operation of a diode-pumped Yb:KGW laser was demonstrated. Near-transform-limited 428 fs pulses were yielded at 1031.1 nm with an output power of 504 mW, corresponding to the ... [Appl. Phys. Lett. 99, 261107 (2011)] published Thu Dec 29, 2011.
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On-chip single photon emission from an integrated semiconductor quantum dot into a photonic crystal waveguide

Andre Schwagmann, Sokratis Kalliakos, Ian Farrer, Jonathan P. Griffiths, Geb A. C. Jones et al.
We demonstrate the in-plane emission of highly polarized single photons from an InAs quantum dot embedded into a photonic crystal waveguide. The spontaneous emission rates are Purcell-enhanced by the coupling of the quantum dot to a slow-light mode of the waveguide. Photon-correlation measurements c ... [Appl. Phys. Lett. 99, 261108 (2011)] published Thu Dec 29, 2011.
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Low-loss flake-graphene saturable absorber mirror for laser mode-locking at sub-200-fs pulse duration

B. V. Cunning, C. L. Brown, and D. Kielpinski
Saturable absorbers are a key component for mode-locking femtosecond lasers. Polymer films containing graphene flakes have recently been used in transmission as laser mode-lockers but suffer from high nonsaturable loss, limiting their application in low-gain lasers. Here, we present a saturable abso ... [Appl. Phys. Lett. 99, 261109 (2011)] published Thu Dec 29, 2011.
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Effect of temperature and strain on the optical polarization of (In)(Al)GaN ultraviolet light emitting diodes

Tim Kolbe, Arne Knauer, Chris Chua, Zhihong Yang, Viola Kueller et al.
The temperature and strain dependence of the polarization of the in-plane electroluminescence of (0001) orientated (In)(Al)GaN multiple quantum well light emitting diodes in the ultraviolet spectral range has been investigated. For light emitting diodes with emission wavelength shorter than 300 nm t ... [Appl. Phys. Lett. 99, 261105 (2011)] published Wed Dec 28, 2011.
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Microfabricated continuous cubic phase plate induced Airy beams for optical manipulation with high power efficiency

Rui Cao, Yong Yang, Jingang Wang, Jing Bu, Mingwei Wang et al.
We studied and demonstrated optical trapping capabilities of an Airy beam generated with a cubic phase plate incorporated into a conventional optical tweezer system. The power efficiency and damage threshold of the cubic phase plate were found to be much higher when spatial light modulators were emp ... [Appl. Phys. Lett. 99, 261106 (2011)] published Wed Dec 28, 2011.
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High power, continuous wave, quantum cascade ring laser

Y. Bai, S. Tsao, N. Bandyopadhyay, S. Slivken, Q. Y. Lu et al.
We demonstrate a quantum cascade ring laser with high power room temperature continuous wave operation. A second order distributed feedback grating buried inside the waveguide provides both in-plane feedback and vertical power outcoupling. Total output power reaches 0.51 W at an emission wavelength ... [Appl. Phys. Lett. 99, 261104 (2011)] published Wed Dec 28, 2011.
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Realization of tightly confined channel plasmon polaritons at low frequencies

Tao Jiang, Linfang Shen, Jin-Jei Wu, Tzong-Jer Yang, Zhichao Ruan et al.
Subwavelength guiding of channel plasmon polaritons (CPPs) is realized by a properly structured metallic groove at frequencies far below the plasma frequency of metal. Compared with CPPs at visible frequencies, more versatile physical mechanisms can be introduced in these CPPs by surface patterning, ... [Appl. Phys. Lett. 99, 261103 (2011)] published Tue Dec 27, 2011.
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Wavelength tunable ultraviolet laser emission via intra-cavity frequency doubling of an AlGaInP vertical external-cavity surface-emitting laser down to 328 nm

T. Schwarzback, H. Kahle, M. Eichfelder, R. Rossbach, M. Jetter et al.
We demonstrate an optically pumped vertical external-cavity surface-emitting laser in a compact v-shaped cavity configuration for frequency doubling to the ultraviolet (UV) spectral range at ~330 nm. The fundamental red laser emission is realized with a metal-organic vapor-phase epitaxy grown (GaIn) ... [Appl. Phys. Lett. 99, 261101 (2011)] published Tue Dec 27, 2011.
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Effect of asymmetric Schottky barrier on GaN-based metal-semiconductor-metal ultraviolet detector

Dabing Li, Xiaojuan Sun, Hang Song, Zhiming Li, Hong Jiang et al.
An asymmetric Schottky barrier metal-semiconductor-metal (MSM) ultraviolet (UV) detector with Ni/GaN/Au structure was designed and the effect of the asymmetric Schottky barrier on the detector response was investigated. This detector had response at 0 V bias and increased responsivity when a positiv ... [Appl. Phys. Lett. 99, 261102 (2011)] published Tue Dec 27, 2011.
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Detecting surface acoustic wave gyroscopic signal by acousto-optic coupling

Shuxiang Lu, Shufen Chen, Honglang Li, Lei Fu, Zhengfeng Zou et al.
A technique for surface acoustic wave (SAW) gyroscopic signal detection by acousto-optic coupling is presented in this article. The principles of the technique and the detection structure were analyzed, and experiments were conducted using the gyroscope. The static results show that the maximum coup ... [Appl. Phys. Lett. 99, 251116 (2011)] published Fri Dec 23, 2011.
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Asymmetry of carrier transport leading to efficiency droop in GaInN based light-emitting diodes

David S. Meyaard, Guan-Bo Lin, Qifeng Shan, Jaehee Cho, E. Fred Schubert et al.
The effect of the asymmetry in carrier concentration and mobility is studied in GaInN pn-junction light-emitting diodes (LEDs). We propose and present experimental evidence that the asymmetry in carrier concentration and mobility, and associated high-level injection phenomena, cause efficiency droop ... [Appl. Phys. Lett. 99, 251115 (2011)] published Fri Dec 23, 2011.
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Quantum efficiency control of InGaN/GaN multi-quantum-well structures using Ag/SiO core-shell nanoparticles

Lee-Woon Jang, Trilochan Sahoo, Dae-Woo Jeon, Myoung Kim, Ju-Won Jeon et al.
Photoluminescence (PL) efficiency increase up to 2.8 times was observed for GaN/InGaN multi-quantum-well (MQW) structures as a result of deposition of a thin layer of about 40-nm-diameter Ag nanoparticles (NPs) surrounded by SiO shell. These Ag/SiO NPs were prepared by sol-gel method. The amount of ... [Appl. Phys. Lett. 99, 251114 (2011)] published Fri Dec 23, 2011.
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Room temperature lasing with high group index in metal-coated GaN nanoring

Yow-Gwo Wang, Shu-Wei Chang, Cheng-Chang Chen, Ching-Hsueh Chiu, Ming-Yen Kuo et al.
The room temperature lasing action from a metal-coated GaN nanoring cavity was observed by optical pumping. The GaN nanoring is 7 [mu]m in diameter and 400 nm in width. The quality factor of the cavity is approximately 860 with a threshold power density of 37.5 mJ/cm. Such a device performance was a ... [Appl. Phys. Lett. 99, 251111 (2011)] published Thu Dec 22, 2011.
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Electroluminescence from Si nanocrystal/c-Si heterojunction light-emitting diodes

Dawei Di, Ivan Perez-Wurfl, Lingfeng Wu, Yidan Huang, Alessandro Marconi et al.
Silicon nanocrystals have shown attractive properties for photonic and photovoltaic applications. We demonstrate all-Si light-emitting diodes based on boron-doped Si nanocrystal/c-Si p-n heterojunction structure, which show electroluminescence in the visible/infrared regions. The electroluminescence ... [Appl. Phys. Lett. 99, 251113 (2011)] published Thu Dec 22, 2011.
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Significantly improved minority carrier lifetime observed in a long-wavelength infrared III-V type-II superlattice comprised of InAs/InAsSb

E. H. Steenbergen, B. C. Connelly, G. D. Metcalfe, H. Shen, M. Wraback et al.
Time-resolved photoluminescence measurements reveal a minority carrier lifetime of >412 ns at 77 K under low excitation for a long-wavelength infrared InAs/InAsSb type-II superlattice (T2SL). This lifetime represents an order-of-magnitude increase in the minority carrier lifetime over previously rep ... [Appl. Phys. Lett. 99, 251110 (2011)] published Thu Dec 22, 2011.
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