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17 Dec 2012

Volume 101, Issue 25, Articles (25xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 101, 251102 (2012); http://dx.doi.org/10.1063/1.4770503 (4 pages)

Haider Butt, Tim Butler, Yunuen Montelongo, Ranjith Rajesekharan, Timothy D. Wilkinson, and Gehan A. J. Amaratunga
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A simplified GaN/AlGaN quantum cascade detector with an alloy extractor

S. Sakr, E. Giraud, M. Tchernycheva, N. Isac, P. Quach, E. Warde, N. Grandjean, and F. H. Julien

Appl. Phys. Lett. 101, 251101 (2012); http://dx.doi.org/10.1063/1.4772501 (4 pages) | Cited 2 times

Online Publication Date: 17 December 2012

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We have demonstrated a GaN/AlGaN quantum cascade detector based on a simplified design of the extractor region relying on an AlGaN thick layer. The device grown by molecular beam epitaxy exhibits both TM-polarized intersubband absorption and photocurrent at room temperature at a peak wavelength of 1.87 μm. Based on the measured absorption and responsivity, we estimate the transfer efficiency of photoelectrons to the next period to be around 62%. This simplified design is robust against thickness fluctuations in the extractor region and offers prospects for ultrafast detectors.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Continuous diffraction patterns from circular arrays of carbon nanotubes

Haider Butt, Tim Butler, Yunuen Montelongo, Ranjith Rajesekharan, Timothy D. Wilkinson, and Gehan A. J. Amaratunga

Appl. Phys. Lett. 101, 251102 (2012); http://dx.doi.org/10.1063/1.4770503 (4 pages)

Online Publication Date: 17 December 2012

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We report the remarkable diffraction effects produced from circular patterned arrays of multiwalled carbon nanotubes (MWCNTs). Highly ordered circular arrays of multiwalled carbon nanotubes (with inter-nanotube spacings of 633 nm) display optical dispersion effects similar to compact discs. These arrays display remarkable diffraction patterns in the far field which are spatially continuous. High quality diffraction patterns were obtained experimentally which are in excellent agreement with the theoretical calculations. The achieved continuous diffraction patterns pave the way towards the utilization of engineered carbon nanotube arrays in applications like three dimensional holograms.
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81.16.-c Methods of micro- and nanofabrication and processing
78.67.Ch Nanotubes

Three-dimensional localization of fluorescent targets in turbid media using time reversal optical tomography

Binlin Wu, W. Cai, and S. K. Gayen

Appl. Phys. Lett. 101, 251103 (2012); http://dx.doi.org/10.1063/1.4771997 (5 pages)

Online Publication Date: 17 December 2012

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An optical tomography approach for locating fluorescent targets embedded inside a turbid medium is introduced. It uses multi-source probing and multi-detector signal acquisition to collect diffuse fluorescence signal, and time reversal matrix formalism with subspace based signal processing for image reconstruction. It could provide three-dimensional position co-ordinates of two small fluorescent targets embedded in Intralipid-20% suspension of thickness ∼60 times the transport mean free path with an accuracy of ∼1 mm. Fast reconstruction and high spatial resolution make the approach potentially suited for detecting and locating contrast-enhanced breast tumor at early stages of growth.
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87.57.nf Reconstruction
82.70.Kj Emulsions and suspensions

Ultrafast polarization modulation in vertical cavity surface emitting lasers with frequency dependent current injection

A. V. Barve, Y. Zheng, L. Johansson, A. Mehta, A. Husain, and L. Coldren

Appl. Phys. Lett. 101, 251104 (2012); http://dx.doi.org/10.1063/1.4772540 (4 pages)

Online Publication Date: 18 December 2012

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We report on a polarization modulation in vertical cavity surface emitting lasers (VCSEL), based on RF electrical injection. Complex polarization dynamics in the single mode regime is studied as a function of RF frequency and power at different bias currents. It has been observed that the polarization state of the VCSEL can be altered by changing the frequency of RF current modulation. Time resolved measurements show that by injecting periodic bursts of RF modulation in the VCSEL, it is possible to change the dominant polarization between the two orthogonal modes at gigahertz rates.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Mode latching and self tuning of whispering gallery modes in a stand-alone silica microsphere

Monica Agarwal and Iwao Teraoka

Appl. Phys. Lett. 101, 251105 (2012); http://dx.doi.org/10.1063/1.4772629 (4 pages)

Online Publication Date: 18 December 2012

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Performance of whispering gallery mode resonators can be compromised by resonance wavelength fluctuations. Here, we employ a silica microsphere coupled with a pair of head-on, single-ended tapers to show that the resonator by itself can latch onto a specific mode when the wavelength of a high-power laser changes over many resonance peak widths in both directions. We also show that, at high power of pump-in laser, the resonator can self-tune its resonance to a fixed wavelength when the resonator temperature changes or the gas flow surrounding the resonator changes, but the resonance is easily lost when the power is low.
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42.79.Gn Optical waveguides and couplers

Quantum yield of luminescence of Ag nanoclusters dispersed within transparent bulk glass vs. glass composition and temperature

A. S. Kuznetsov, J. J. Velázquez, V. K. Tikhomirov, J. Mendez-Ramos, and V. V. Moshchalkov

Appl. Phys. Lett. 101, 251106 (2012); http://dx.doi.org/10.1063/1.4772957 (5 pages) | Cited 1 time

Online Publication Date: 19 December 2012

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The intensity, lifetime, and quantum yield of luminescence of Ag nanoclusters dispersed within transparent oxyfluoride glass host are shown to vary over an order of magnitude with varying glass composition and temperature. In particular, the yield may vary with glass composition from 2% to 30% at room temperature and up to 50% with decreasing temperature to 25 K, when excited at some wavelengths in ultraviolet. These variations are suggested to be governed by the change in the F-interstitials/Frenkel defects concentration, and temperature dependence of spin flip and F-interstitials assisted non-radiative decay of the photoexcited electrons on Ag nanoclusters.
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78.55.Hx Other solid inorganic materials
61.72.jd Vacancies
61.72.jj Interstitials
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

2.8 μm emission from type-I quantum wells grown on InAsxP1−x/InP metamorphic graded buffers

Daehwan Jung, Yuncheng Song, Lan Yu, Daniel Wasserman, and Minjoo Larry Lee

Appl. Phys. Lett. 101, 251107 (2012); http://dx.doi.org/10.1063/1.4773024 (4 pages) | Cited 2 times

Online Publication Date: 19 December 2012

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We report 2.8 μm emission from compressively strained type-I quantum wells (QWs) grown on InP-based metamorphic InAsxP1−x step-graded buffers. High quality metamorphic graded buffers showed smooth surface morphology and low threading dislocation densities of approximately 2.5 × 106 cm−2. High-resolution x-ray diffraction scans showed strong satellites from multiple quantum wells grown on metamorphic buffers, and cross-sectional transmission electron microscopy revealed smooth and coherent quantum well interfaces. Room-temperature photoluminescence emission at 2.8 μm with a narrow linewidth (∼50 meV) shows the promise of metamorphic growth for mid-infrared laser diodes on InP.
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78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
78.67.De Quantum wells
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.ag Semiconductors
68.65.Fg Quantum wells

Radiation tolerance characterization of dual band InAs/GaSb type-II strain-layer superlattice pBp detectors using 63 MeV protons

V. M. Cowan, C. P. Morath, J. E. Hubbs, S. Myers, E. Plis, and S. Krishna

Appl. Phys. Lett. 101, 251108 (2012); http://dx.doi.org/10.1063/1.4772543 (4 pages)

Online Publication Date: 19 December 2012

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The radiation tolerance characterization of dual band InAs/GaSb type-II strain-layer superlattice pBp detectors of varying size using 63 MeV proton irradiation is presented. The detectors' mid-wave infrared performance degraded with increasing proton fluence ΦP up to 3.75 × 1012 cm−2 or, equivalently, a total ionizing dose = 500 kRad (Si). At this ΦP, an ∼31% drop in quantum efficiency η, ∼2 order increase in dark current density JD, and consequently, >1 order drop in calculated detectivity D* were observed. Proton damage factors were determined for η and D*. Arrhenius-analysis of temperature-dependent JD measurements reflected significant changes in the activation energies following irradiation.
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61.80.Jh Ion radiation effects
68.65.Cd Superlattices

Electrical modulation of the optical properties of mid-infrared metamaterials

K. Larsen, D. Austin, I. C. Sandall, D. G. Davies, D. G. Revin, J. W. Cockburn, A. M. Adawi, R. J. Airey, P. W. Fry, M. Hopkinson, and L. R. Wilson

Appl. Phys. Lett. 101, 251109 (2012); http://dx.doi.org/10.1063/1.4772545 (3 pages)

Online Publication Date: 19 December 2012

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We present a hybrid, mid-infrared metamaterial device, consisting of a near-surface semiconductor quantum well beneath a gold split ring resonator array. Electrical control of the free carrier concentration in the near-surface quantum well allows variation of the refractive index within the fringing field of the split ring resonator array. We observe a 10% transmission change at the fundamental resonance of the split ring resonators, in very good agreement with simulations. For optimised structures, we predict a 10% wavelength shift of the fundamental resonance, with important implications for optical components such as switches and spatial light modulators.
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85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.67.Pt Multilayers; superlattices; photonic structures; metamaterials

Local photocurrent generation in thin films of the topological insulator Bi2Se3

C. Kastl, T. Guan, X. Y. He, K. H. Wu, Y. Q. Li, and A. W. Holleitner

Appl. Phys. Lett. 101, 251110 (2012); http://dx.doi.org/10.1063/1.4772547 (4 pages)

Online Publication Date: 19 December 2012

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We report on the optoelectronic properties of thin films of Bi2Se3 grown by molecular beam epitaxy. The films are patterned into circuits with typical extensions of tens of microns. In spatially resolved experiments, we observe submicron photocurrent patterns with positive and negative amplitudes. The patterns are independent of the applied bias voltage, but they depend on the width of the circuits. We interpret the patterns to originate from a local photocurrent generation due to potential fluctuations.
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73.50.Pz Photoconduction and photovoltaic effects
73.61.Ng Insulators
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
72.40.+w Photoconduction and photovoltaic effects

Energy transfer between few-cycle laser filaments in air

Cheng Gong, Yinghui Zheng, Yue Zhong, Zhinan Zeng, Chuang Li, Xiaochun Ge, Ruxin Li, and Zhizhan Xu

Appl. Phys. Lett. 101, 251111 (2012); http://dx.doi.org/10.1063/1.4772591 (4 pages)

Online Publication Date: 19 December 2012

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We report on the energy exchange between two filaments generated by few-cycle mid-infrared laser in air. The direction of energy transfer vs the relative time delay is demonstrated distinctly as oscillations with a period of optical cycle. In addition, benefitting from the broadband spectrum of few-cycle laser pulses, we confirm an unreported fine spectral structure of energy transfer when the relative time delay is changed. The simulation results obtained by using a generalized two-beam coupling model agree well with the experimental results. A simple analytical expression has been deduced to explain the fine structure of energy transfer.
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42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
42.65.Re Ultrafast processes; optical pulse generation and pulse compression

Three-dimensional Maxwell-Bloch calculation of the temporal profile of a seeded soft x-ray laser pulse

F. Tissandier, S. Sebban, J. Gautier, Ph. Zeitoun, E. Oliva, A. Rousse, and G. Maynard

Appl. Phys. Lett. 101, 251112 (2012); http://dx.doi.org/10.1063/1.4773208 (4 pages) | Cited 1 time

Online Publication Date: 19 December 2012

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We present three-dimensional modeling of amplification of a high-order harmonic seed by a soft x-ray laser plasma. The time-dependent evolution of the x-ray signal is determined from a fully dynamic Maxwell-Bloch calculation. At high seed intensities, a simplified one-dimensional calculation leads to strong Rabi-like temporal oscillations of the output signal. However, such oscillations have not been observed experimentally. Our calculations demonstrate that this is due to spatial non-uniformities in the plasma gain that cause the Rabi oscillations to dampen dramatically. Large amplitude Rabi-like oscillations are expected to appear only in long and uniform plasma. Such targets require optimized guiding techniques.
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.79.Nv Optical frequency converters
41.50.+h X-ray beams and x-ray optics

Experimental demonstration of a four-port photonic crystal cross-waveguide structure

Yi Yu, Mikkel Heuck, Sara Ek, Nadezda Kuznetsova, Kresten Yvind, and Jesper Mørk

Appl. Phys. Lett. 101, 251113 (2012); http://dx.doi.org/10.1063/1.4772942 (4 pages)

Online Publication Date: 20 December 2012

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We report the design and fabrication of a four-port InP photonic crystal cavity-waveguide structure in which two crossing waveguides intersect in a cavity. Transmission measurements show that by exploiting mode-gap effects, high cross-talk suppression between the two waveguides can be obtained. In addition, the waveguides couple to two distinct cavity resonances with different quality-factors as well as small mode volumes. This structure is promising for realizing ultra-fast, low-energy optical switches or memories.
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42.79.Gn Optical waveguides and couplers
42.70.Qs Photonic bandgap materials

A three-dimensional, polarization-insensitive superconducting nanowire avalanche photodetector

V. B. Verma, F. Marsili, S. Harrington, A. E. Lita, R. P. Mirin, and S. W. Nam

Appl. Phys. Lett. 101, 251114 (2012); http://dx.doi.org/10.1063/1.4768788 (4 pages) | Cited 3 times

Online Publication Date: 20 December 2012

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We demonstrate an approach to improving the detection efficiency, removing the polarization dependence, and increasing the signal-to-noise ratio of conventional superconducting nanowire single photon detectors (SNSPDs) by vertically stacking two WSi SNSPDs and electrically connecting them in parallel, forming a three-dimensional superconducting nanowire avalanche photodetector. We measure a peak system detection efficiency of 87.7% ± 0.5% and a polarization dependence of less than 2%, representing nearly an order of magnitude improvement in both system detection efficiency and reduction of polarization dependence compared to conventional SNSPDs.
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85.25.Oj Superconducting optical, X-ray, and γ-ray detectors (SIS, NIS, transition edge)
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices

Effect of the number of quantum dot layers and dual state emission on the performance of InAs/InGaAs passively mode-locked lasers

Charis Mesaritakis, Christos Simos, Hercules Simos, Alexandros Kapsalis, Eugenia Roditi, Igor Krestnikov, and Dimitris Syvridis

Appl. Phys. Lett. 101, 251115 (2012); http://dx.doi.org/10.1063/1.4772592 (4 pages)

Online Publication Date: 20 December 2012

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In this paper, a series of quantum-dot passively mode-locked Fabry-Perot lasers has been experimentally investigated. The devices vary in terms of number of quantum dot layers, thus allowing the extraction of guidelines regarding the impact of this parameter on the quality of mode locking. Although, theoretical estimations imply that the increase of the quantum dot layers can enhance the emitted optical power but degrade mode-locking stability, the experimental evaluation proved that the existence of dual wavelength emission can affect this trend and allow better performance from devices that do not exhibit excited state emission.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Fc Modulation, tuning, and mode locking
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Femtosecond laser induced surface deformation in multi-dimensional data storage

Yanlei Hu, Yuhang Chen, Jiawen Li, Daqiao Hu, Jiaru Chu, Qijin Zhang, and Wenhao Huang

Appl. Phys. Lett. 101, 251116 (2012); http://dx.doi.org/10.1063/1.4772937 (4 pages)

Online Publication Date: 21 December 2012

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We investigate the surface deformation in two-photon induced multi-dimensional data storage. Both experimental evidence and theoretical analysis are presented to demonstrate the surface characteristics and formation mechanism in azo-containing material. The deformation reveals strong polarization dependence and has a topographic effect on multi-dimensional encoding. Different stages of data storage process are finally discussed taking into consideration the surface deformation formation.
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68.35.Gy Mechanical properties; surface strains
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity
68.35.bm Polymers, organics

Efficient coupler between silicon photonic and metal-insulator-silicon-metal plasmonic waveguides

A. Emboras, R. M. Briggs, A. Najar, S. Nambiar, C. Delacour, Ph. Grosse, E. Augendre, J. M. Fedeli, B. de Salvo, H. A. Atwater, and R. Espiau de Lamaestre

Appl. Phys. Lett. 101, 251117 (2012); http://dx.doi.org/10.1063/1.4772941 (4 pages)

Online Publication Date: 21 December 2012

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We report the experimental realization of a compact, efficient coupler between silicon waveguides and vertical metal-insulator-silicon-metal (MISM) plasmonic waveguides. Devices were fabricated using complementary metal-oxide-silicon technology processes, with copper layers that support low-loss plasmonic modes in the MISM structures at a wavelength of 1550 nm. By implementing a short (0.5 μm) optimized metal-insulator-silicon-insulator structure inserted between the photonic and plasmonic waveguide sections, we demonstrate experimental coupling loss of 2.5 dB, despite the high optical confinement of the MISM mode and mismatch with the silicon waveguide mode.
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42.79.Gn Optical waveguides and couplers
42.82.-m Integrated optics
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)

Polarization-resolved resonant fluorescence of a single semiconductor quantum dot

J. Robertson, S. Founta, M. Hughes, M. Hopkinson, A. J. Ramsay, M. S. Skolnick, and C. K. Shih

Appl. Phys. Lett. 101, 251118 (2012); http://dx.doi.org/10.1063/1.4772495 (4 pages)

Online Publication Date: 21 December 2012

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We observe the resonantly excited emission of a single self assembled quantum dot (QD) positioned in a planar μ-cavity, free of any background scattering from defects in the surrounding lattice matrix. Making use of this technique, we are able to obtain the second-order correlation function g2(τ) and, therefore, observe its oscillations under strong continuous-wave excitation. By determining that its correlation function is near zero for g2(τ = 0), we are able to verify its status as a single quantum emitter. By altering the input scheme geometry, we are also able to demonstrate further direct control of a single QD's properties by gaining access to and observing emission from both of its polarization states πx and πy by merely tuning the excitation wavelength.
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78.67.Hc Quantum dots
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors

Sub-diffraction optical coherent control of ultrafast electrical currents in antenna devices on GaAs

Sebastian Thunich, Claudia Ruppert, Alexander W. Holleitner, and Markus Betz

Appl. Phys. Lett. 101, 251119 (2012); http://dx.doi.org/10.1063/1.4773028 (4 pages)

Online Publication Date: 21 December 2012

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Femtosecond ω/2ω pulse pairs derived from a compact Er:fibre source induce coherently controlled currents in low temperature grown GaAs. They are characterized by analyzing charge accumulation at contacts closeby. We focus on the photoresponse of bowtie optical antennas integrated into such metal-semiconductor-metal structures. Antennas are designed to enhance the ω field and to confine it into the 50 nm antenna gap. The coherently controlled current is markedly enhanced by the plasmonic nanostructure. However, we find an only unpronounced dependence on the antenna length which is probably related to the large refractive index of GaAs and intricate resonance conditions for ultrabroadband excitation light.
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42.79.-e Optical elements, devices, and systems
42.79.Dj Gratings
42.82.-m Integrated optics
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
42.50.-p Quantum optics
42.65.Re Ultrafast processes; optical pulse generation and pulse compression

Random lasing in structures with multi-scale transport properties

Marco Leonetti and Cefe Lopez

Appl. Phys. Lett. 101, 251120 (2012); http://dx.doi.org/10.1063/1.4773056 (4 pages)

Online Publication Date: 21 December 2012

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In a random laser (RL), a system possessing in itself both resonator and amplifying medium while lacking a macroscopic cavity, the feedback is provided by the scattering, which forces light to travel very long random paths. Here, we demonstrate that RL properties may be tuned by the topology of the scattering system retaining unchanged scattering strength and gain efficiency. This is possible in a system based on sparse clusters, possessing two relevant structural lengths: the macroscopic inter cluster separation and the mesoscopic intra-cluster mean free path.
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42.60.Fc Modulation, tuning, and mode locking
42.79.-e Optical elements, devices, and systems
42.55.-f Lasers
42.60.-v Laser optical systems: design and operation

Widely tuned room temperature terahertz quantum cascade laser sources based on difference-frequency generation

Q. Y. Lu, N. Bandyopadhyay, S. Slivken, Y. Bai, and M. Razeghi

Appl. Phys. Lett. 101, 251121 (2012); http://dx.doi.org/10.1063/1.4773189 (4 pages) | Cited 2 times

Online Publication Date: 21 December 2012

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We demonstrate room temperature THz quantum cascade laser sources with a broad spectral coverage based on intracavity difference-frequency generation. Two mid-infrared active cores based on the single-phonon resonance scheme are designed with a THz nonlinearity specially optimized at the high operating fields that correspond to the highest mid-infrared output powers. A Čerenkov phase-matching scheme along with integrated dual-period distributed feedback gratings are used for efficient THz extraction and spectral purification. Single mode emissions from 1.0 to 4.6 THz with a side-mode suppression ratio and output power up to 40 dB and 32 μW are obtained, respectively.
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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.-k Nonlinear optics
42.79.Dj Gratings
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Dual electrode cantilevers for ohmic microscopy

Markus Ignatowitz and Egbert Oesterschulze

Appl. Phys. Lett. 101, 251601 (2012); http://dx.doi.org/10.1063/1.4772483 (3 pages)

Online Publication Date: 17 December 2012

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Spatially resolved electrochemical microscopy with a dual electrode probe necessitates the precise adjustment of the dimensions, geometry, and spacing of the electrodes involved as well as the control of the probe-sample distance. Therefore, we introduce a microfabricated atomic force microscopy cantilever probe consisting of a thin film stack constituting the overlaying dual insulated electrodes. The deposition processes involved impose an inherent precision in one dimension of typically 10 nm. Spatially resolved dual electrode ohmic microscopy measurements demonstrate its sensitivity to electrochemical material contrast and the progress by improving the lateral resolution by two decades.
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82.80.Fk Electrochemical methods
07.68.+m Photography, photographic instruments; xerography
07.79.Lh Atomic force microscopes

Identifying graphene layers via spin Hall effect of light

Xinxing Zhou, Xiaohui Ling, Hailu Luo, and Shuangchun Wen

Appl. Phys. Lett. 101, 251602 (2012); http://dx.doi.org/10.1063/1.4772502 (4 pages)

Online Publication Date: 18 December 2012

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The spin Hall effect (SHE) of light is a useful metrological tool for characterizing the structure parameters' variations of nanostructure. In this letter, we propose using the SHE of light to identify the graphene layers. This technique is based on the mechanism that the transverse displacements in SHE of light are sensitive to the variations of graphene layer numbers.
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73.61.Wp Fullerenes and related materials
72.80.Vp Electronic transport in graphene
72.20.My Galvanomagnetic and other magnetotransport effects
72.25.-b Spin polarized transport

Controlled manipulation of wetting characteristics of nanoparticles with dry-based plasma polymerization method

Anaram Shahravan, Tapan Desai, and Themis Matsoukas

Appl. Phys. Lett. 101, 251603 (2012); http://dx.doi.org/10.1063/1.4772544 (4 pages)

Online Publication Date: 18 December 2012

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A dry process for tailoring nanoparticle wetting characteristics using plasma enhanced chemical vapor deposition technique is established. The “plasma polymer” coating imparts the properties of the precursors used in the plasma technique, without the requirement for nanoparticle surface preparation. For a range of chosen precursors, the water contact angle of a sessile droplet on coated copper oxide nanoparticles was shown to vary from 54° to 76°, 92° to 108°. Stable suspensions of coated nanoparticles were demonstrated.
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61.46.Df Structure of nanocrystals and nanoparticles ("colloidal" quantum dots but not gate-isolated embedded quantum dots)
68.03.Cd Surface tension and related phenomena
81.07.Bc Nanocrystalline materials
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
82.35.-x Polymers: properties; reactions; polymerization
82.70.Kj Emulsions and suspensions

Investigation of photoelectrochemical-oxidized p-GaSb films

Hsin-Ying Lee, Hung-Lin Huang, Ching-Ting Lee, Oleg Petrovich Pchelyakov, and Nikolay Andreevich Pakhanov

Appl. Phys. Lett. 101, 251604 (2012); http://dx.doi.org/10.1063/1.4772497 (4 pages)

Online Publication Date: 19 December 2012

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GaSb oxide films were directly formed on the p-GaSb films using the bias-assisted photoelectrochemical (PEC) oxidation method. X-ray photoelectron spectroscopy analysis indicated that the resulting GaSb oxide films consisted of Ga2O3, Sb2O3, and Sb2O5. Different from the non-PEC oxides, the PEC derived oxide contained much more Sb2O5 than Sb2O3. Besides, the interface state density between the PEC oxide and p-GaSb was lower than that of the ordinary oxide/p-GaSb interface. The high quality of the PEC-oxidized GaSb films was attributed to the increase of the stable Sb2O5 content and decrease of the elemental Sb content in the films.
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82.45.-h Electrochemistry and electrophoresis
82.50.Kx Processes caused by X-rays or γ-rays
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
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