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19 Jul 2010

Volume 97, Issue 3, Articles (03xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 97, 033102 (2010); http://dx.doi.org/10.1063/1.3431661 (3 pages)

Youngki Yoon and Sayeef Salahuddin
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Terahertz activated luminescence of trapped carriers in InGaAs/GaAs quantum dots

J. Bhattacharyya, M. Wagner, M. Helm, M. Hopkinson, L. R. Wilson, and H. Schneider

Appl. Phys. Lett. 97, 031101 (2010); http://dx.doi.org/10.1063/1.3464163 (3 pages) | Cited 2 times

Online Publication Date: 19 July 2010

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Optical properties and interdot transfer dynamics of trapped carriers in InGaAs quantum dots (QDs) are investigated. Time resolved photoluminescence (PL) was measured for time-delayed interband and intraband excitations. Terahertz activated luminescence (TAL) from trapped carriers having lifetimes of ∼ 250 ns at 8 K, was observed. Spectral shift of the TAL with respect to the PL showed the trionic nature of the PL in the n-doped QDs. With increasing terahertz excitation intensity, the TAL increased and reached saturation. The activation energy associated with the trapped carrier decay was quite close to the intersublevel transition energy ( ∼ 20 meV) indicating trapping in the QDs.
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78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors

Efficient photon number detection with silicon avalanche photodiodes

O. Thomas, Z. L. Yuan, J. F. Dynes, A. W. Sharpe, and A. J. Shields

Appl. Phys. Lett. 97, 031102 (2010); http://dx.doi.org/10.1063/1.3464556 (3 pages) | Cited 10 times

Online Publication Date: 19 July 2010

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We demonstrate an efficient photon number detector for visible wavelengths using a silicon avalanche photodiode. Under subnanosecond gating, the device is able to resolve up to four photons in an incident optical pulse. The detection efficiency at 600 nm is measured to be 73.8%, corresponding to an avalanche probability of 91.1% of the absorbed photons, with a dark count probability below 1.1×10−6 per gate. With this performance and operation close to room temperature, fast-gated silicon avalanche photodiodes are ideal for optical quantum information processing that requires single-shot photon number detection.
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85.60.Gz Photodetectors (including infrared and CCD detectors)
85.60.Dw Photodiodes; phototransistors; photoresistors

Excitonic electroluminescence at room temperature in an (In,Ga)As multiple-quantum-well diode

M. Noriyasu and K. Fujiwara

Appl. Phys. Lett. 97, 031103 (2010); http://dx.doi.org/10.1063/1.3464559 (3 pages) | Cited 1 time

Online Publication Date: 19 July 2010

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Electroluminescence (EL) spectra of an In0.15Ga0.85As/Al0.15Ga0.85As multiple-quantum-well p-i-n diode measured at 15–300 K are dominated by the ground heavy-hole exciton transition, as assigned from coincidence to the leading exciton resonance absorption energy. Although most of excitons thermally dissociate into free carriers populated up to the first excited confinement states at room temperature, radiative recombination is strongly enhanced at the exciton states. Simulated EL spectra based on the excitonic absorption spectra rigorously reproduce all of the excitonic EL features superposed on the exponentially tailing emission at the continuum states, showing coexistence of excitons and free carriers at room temperature.
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85.30.Kk Junction diodes

Giant Stark effect in the emission of single semiconductor quantum dots

Anthony J. Bennett, Raj B. Patel, Joanna Skiba-Szymanska, Christine A. Nicoll, Ian Farrer, David A. Ritchie, and Andrew J. Shields

Appl. Phys. Lett. 97, 031104 (2010); http://dx.doi.org/10.1063/1.3460912 (3 pages) | Cited 5 times

Online Publication Date: 19 July 2010

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We study the quantum-confined Stark effect in single InAs/GaAs quantum dots embedded within a AlGaAs/GaAs/AlGaAs quantum well. By significantly increasing the barrier height we can observe emission from a dot at electric fields of 500 kV cm−1, leading to Stark shifts of up to 25 meV. Our results suggest this technique may enable future applications that require self-assembled dots with transitions at the same energy.
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78.20.Jq Electro-optical effects
78.67.Hc Quantum dots

Polariton parametric oscillation in a single micropillar cavity

Lydie Ferrier, Simon Pigeon, Esther Wertz, Motoaki Bamba, Pascale Senellart, Isabelle Sagnes, Aristide Lemaître, Cristiano Ciuti, and Jacqueline Bloch

Appl. Phys. Lett. 97, 031105 (2010); http://dx.doi.org/10.1063/1.3466902 (3 pages) | Cited 2 times

Online Publication Date: 19 July 2010

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We demonstrate parametric oscillation of discrete polariton states in a single squared GaAs/GaAlAs micropillar cavity. Resonantly exciting a selected polariton mode with a continuous wave pump laser, parametric oscillation is evidenced on the two neighbored modes (signal and idler). Abrupt switch-off of the device is observed under high excitation. We present comprehensive results concerning the power-dependence of the energy and linewidth of the emission resonances as well as their far-field patterns. Quantum Monte Carlo calculations give a quantitative understanding of the physics of this micro-optical parametric oscillator involving fully confined discrete polariton modes.
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42.65.Yj Optical parametric oscillators and amplifiers
71.36.+c Polaritons (including photon-phonon and photon-magnon interactions)

Whispering-gallery-mode terahertz pulse propagation on a curved metallic plate

Rajind Mendis and Daniel M. Mittleman

Appl. Phys. Lett. 97, 031106 (2010); http://dx.doi.org/10.1063/1.3466909 (3 pages) | Cited 1 time

Online Publication Date: 19 July 2010

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We demonstrate terahertz (THz) pulse propagation on a cylindrical aluminum plate, with low loss and negligible dispersion via transverse-electric type whispering gallery (WG) modes. We observe an apparent superluminal effect where the group velocity is greater than c, and explain this phenomenon by means of a plane-wave description of the WG modes. The propagation loss is dominated by the diffraction loss due to unbounded lateral spreading, with a negligible ohmic-loss contribution. Both experimental and theoretical results indicate a total loss as low as 2.6 dB/m at a frequency of 0.47 THz.
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42.79.Gn Optical waveguides and couplers
84.40.-x Radiowave and microwave (including millimeter wave) technology

Generation of two-color continuous variable quantum entanglement at 0.8 and 1.5 μm

Yongmin Li, Xiaomin Guo, Zengliang Bai, and Chunchun Liu

Appl. Phys. Lett. 97, 031107 (2010); http://dx.doi.org/10.1063/1.3467045 (3 pages) | Cited 4 times

Online Publication Date: 20 July 2010

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Two-color continuous variable quantum entanglement at 0.8 and 1.5 μm was experimentally demonstrated by using an above-threshold optical parametric oscillator based on a periodically poled KTiOPO4 crystal. The system presented here has potential applications in future quantum information networks, e.g., it can be used to made a connection between a quantum memory device based on alkaline atoms and a quantum communication device based on telecommunication optical fibers.
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42.65.Yj Optical parametric oscillators and amplifiers
42.65.Lm Parametric down conversion and production of entangled photons
42.50.Dv Quantum state engineering and measurements

High peak power λ ∼ 3.3 and 3.5 μm InGaAs/AlAs(Sb) quantum cascade lasers operating up to 400 K

J. P. Commin, D. G. Revin, S. Y. Zhang, A. B. Krysa, K. Kennedy, and J. W. Cockburn

Appl. Phys. Lett. 97, 031108 (2010); http://dx.doi.org/10.1063/1.3464551 (3 pages) | Cited 9 times

Online Publication Date: 20 July 2010

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We demonstrate λ ∼ 3.5 μm and λ ∼ 3.3 μm strain compensated In0.7Ga0.3As/AlAs(Sb)/InP quantum cascade lasers operating in pulse regime at temperatures up to at least 400 K. Peak optical power exceeding 3.5 W at 300 K has been achieved at both wavelengths for 10 μm wide 4 mm long lasers with high reflectivity coated back facets. Threshold current densities of 2.5 kA/cm2 and 3.5 kA/cm2 have been observed at 300 K for the devices emitting at λ ∼ 3.5 μm and λ ∼ 3.3 μm, respectively.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

High numerical aperture microlens arrays of close packing

Dong Wu, Si-Zhu Wu, Li-Gang Niu, Qi-Dai Chen, Rui Wang, Jun-Feng Song, Hong-Hua Fang, and Hong-Bo Sun

Appl. Phys. Lett. 97, 031109 (2010); http://dx.doi.org/10.1063/1.3464979 (3 pages) | Cited 7 times

Online Publication Date: 20 July 2010

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Closed-packed high numerical aperture (NA) microlens arrays (MLA) are highly desirable for high resolution imaging and high signal-to-noise-ratio detection in micro-optical and integrated optical applications. However, realization of such devices remains technically challenging. Here, we report high quality fabrication of curved surfaces and MLAs by taking the full advantage of surface self-smoothing effect by creating highly reproducible voxels and by adopting an equal-arc scanning strategy. MLA of approximately 100% fill ratio and NA of 0.46, much greater than those ever reported, 0.13, is demonstrated, whose excellent optical performance was approved by the sharp focusing and high resolution imaging.
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42.79.Bh Lenses, prisms and mirrors
42.82.Cr Fabrication techniques; lithography, pattern transfer

InGaN staircase electron injector for reduction of electron overflow in InGaN light emitting diodes

X. Ni, X. Li, J. Lee, S. Liu, V. Avrutin, Ü. Özgür, H. Morkoç, A. Matulionis, T. Paskova, G. Mulholland, and K. R. Evans

Appl. Phys. Lett. 97, 031110 (2010); http://dx.doi.org/10.1063/1.3465658 (3 pages) | Cited 9 times

Online Publication Date: 20 July 2010

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Ballistic and quasiballistic electron transport across the active InGaN layer are shown to be responsible for electron overflow and electroluminescence efficiency droop at high current levels in InGaN light emitting diodes both experimentally and by first-order calculations. An InGaN staircase electron injector with step-like increased In composition, an “electron cooler,” is proposed for an enhanced thermalization of the injected hot electrons to reduce the overflow and mitigate the efficiency droop. The experimental data show that the staircase electron injector results in essentially the same electroluminescence performance for the diodes with and without an electron blocking layer, confirming substantial electron thermalization. On the other hand, if no InGaN staircase electron injector is employed, the diodes without the electron blocking layer have shown significantly lower (three to five times) electroluminescence intensity than the diodes with the blocking layer. These results demonstrate a feasible method for the elimination of electron overflow across the active region, and therefore, the efficiency droop in InGaN light emitting diodes.
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85.60.Jb Light-emitting devices

Terahertz time-domain-spectroscopy system based on femtosecond Yb:fiber laser and GaBiAs photoconducting components

V. Pačebutas, A. Bičiūnas, S. Balakauskas, A. Krotkus, G. Andriukaitis, D. Lorenc, A. Pugžlys, and A. Baltuška

Appl. Phys. Lett. 97, 031111 (2010); http://dx.doi.org/10.1063/1.3458826 (3 pages) | Cited 4 times

Online Publication Date: 20 July 2010

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We describe a terahertz time-domain-spectroscopy system that is based on photoconductive components fabricated from low-temperature-grown GaBiAs epitaxial layers and activated by femtosecond 1.03 μm pulses emitted by an Yb:fiber laser. Experiments performed with the laser pulses of different durations have evidenced that the spectral range of the system is limited by the photoexcited carrier lifetime. The optical to terahertz conversion efficiency of the system exceeds 10−4 with the usable spectral range of about 3 THz in the case of 170 fs excitation pulses.
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07.57.Pt Submillimeter wave, microwave and radiowave spectrometers; magnetic resonance spectrometers, auxiliary equipment, and techniques
42.62.Fi Laser spectroscopy

Near field photothermal printing of gold microstructures and nanostructures

Fan Xiao, Ting-Hsiang Wu, and Pei Yu Chiou

Appl. Phys. Lett. 97, 031112 (2010); http://dx.doi.org/10.1063/1.3459977 (3 pages) | Cited 3 times

Online Publication Date: 21 July 2010

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We report on a rapid near field photothermal printing (NPTP) approach for fabricating gold microstructures and nanostructures guided by flexible and transparent polymer molds. The optical energy of nanosecond laser pulse is spatially redistributed by a PDMS phase-shifting mask, resulting in selective gold melting in light intensity enhanced areas. The melted gold migrates to cold areas and forms desired structures after cooled down. Using NPTP, we have demonstrated rapid laser printing of periodic gold nanowire array with a 320 nm linewidth, nanosphere arrays with 400 nm in diameter, and nonperiodic structures across a 1 mm2 area with few laser pulses.
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81.16.Nd Micro- and nanolithography
81.07.Gf Nanowires
85.40.Hp Lithography, masks and pattern transfer
78.20.nb Photothermal effects

Investigation of dominant effect on efficiency droop in InGaN light emitting device

Kyu Sang Kim, Jin Ha Kim, Young Min Park, Su Jin Jung, Yong Jo Park, and S. N. Cho

Appl. Phys. Lett. 97, 031113 (2010); http://dx.doi.org/10.1063/1.3467451 (3 pages) | Cited 2 times

Online Publication Date: 21 July 2010

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To understand a major effect on efficiency droop, radiative characteristics of InGaN laser diodes (LDs) of emission wavelength of ∼ 445 nm are studied at subthreshold levels for different active structures; (1) InGaN single quantum well (SQW), (2) double quantum wells (DQWs) with Si-doped barrier, and (3) DQWs with undoped barrier. For InGaN LDs with DQWs, the absolute radiative efficiency is most dominant for the case of undoped barrier, and least for the case of Si-doped barrier. The efficiency droop in InGaN LDs with DQWs, regardless of the doping condition of barriers, is typical of reported InGaN light emitting devices, whereas for the InGaN LD with SQW, the efficiency droop is significantly improved for all current density levels due to the least polarization field of InGaN QW.
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85.60.Jb Light-emitting devices
61.72.uj III-V and II-VI semiconductors
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.)

Optical properties of graphene nanoribbon in a spatially modulated magnetic field

Jhao-Ying Wu, Li-Han Chen, To-Sing Li, and Ming-Fa Lin

Appl. Phys. Lett. 97, 031114 (2010); http://dx.doi.org/10.1063/1.3467038 (3 pages) | Cited 1 time

Online Publication Date: 22 July 2010

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The low-frequency optical response of graphene nanoribbons can be enhanced and tuned by a spatially modulated magnetic field. The absorption spectrum exhibits rich asymmetric peaks corresponding to the oscillatory behavior in energy bands. The optical selection rule, dominated by magnetic and quantum confinements, is clarified by examining state wave functions. The dependence of the optical excitations on field strength and period is studied as well. These results provide possibility for employing graphene nanoribbons in future optoelectronic applications.
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78.67.Wj Optical properties of graphene
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Terahertz near-field microspectroscopy

J. R. Knab, A. J. L. Adam, R. Chakkittakandy, and P. C. M. Planken

Appl. Phys. Lett. 97, 031115 (2010); http://dx.doi.org/10.1063/1.3467192 (3 pages) | Cited 5 times

Online Publication Date: 22 July 2010

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Using near-field, terahertz time-domain spectroscopy (THz-TDS), we investigate how the addition of a dielectric material into a subwavelength-diameter, cylindrical waveguide affects its transmission properties. The THz electric near-field is imaged with deep subwavelength resolution as it emerges from filled and unfilled waveguides. Spectroscopic data measured for waveguides filled with polycrystalline D-tartaric acid, and with polyethylene and silicon powders, illustrate the feasibility of this approach for obtaining spectroscopic information from a tiny sample volume.
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84.40.Az Waveguides, transmission lines, striplines
85.50.-n Dielectric, ferroelectric, and piezoelectric devices

Effect of thermal treatment on the performance of ZnO based metal-insulator-semiconductor ultraviolet photodetectors

Ghusoon M. Ali and P. Chakrabarti

Appl. Phys. Lett. 97, 031116 (2010); http://dx.doi.org/10.1063/1.3467204 (3 pages) | Cited 4 times

Online Publication Date: 22 July 2010

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The article reports fabrication, characterization, and testing of the performance of ZnO-based metal-insulator-semiconductor (MIS) Schottky barrier ultraviolet photodetectors under varying thermal treatment. The ZnO thin film was grown on p-type Si 〈100〉 substrate by using sol-gel technique. The electrical and optical characteristics of MIS photodetector were studied. The study revealed that the performance of the device improves with increasing postmetal deposition annealing temperature up to 250 °C approximately. For annealing temperature beyond 250 °C the performance of the device degrades drastically. The variation in the electrical and photoresponse properties of MIS photodetector can be attributed to combined effects of interfacial reaction and phase transition during the annealing process.
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85.60.Gz Photodetectors (including infrared and CCD detectors)
85.60.Bt Optoelectronic device characterization, design, and modeling

Quantum entanglement distribution with 810 nm photons through telecom fibers

E. Meyer-Scott, H. Hübel, A. Fedrizzi, C. Erven, G. Weihs, and T. Jennewein

Appl. Phys. Lett. 97, 031117 (2010); http://dx.doi.org/10.1063/1.3460920 (3 pages) | Cited 4 times

Online Publication Date: 22 July 2010

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We demonstrate the distribution of polarization entangled photons of wavelength 810 nm through standard telecom fibers. This technique allows quantum communication protocols to be performed over established fiber infrastructure, and makes use of the smaller and better performing setups available around 800 nm, as compared to those which use telecom wavelengths around 1550 nm. We examine the excitation and subsequent quenching of higher-order spatial modes in telecom fibers up to 6 km in length, and perform a distribution of high quality entanglement (visibility 95.6%). Finally, we demonstrate quantum key distribution using entangled 810 nm photons over a 4.4 km long installed telecom fiber link.
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03.67.Hk Quantum communication
03.67.Bg Entanglement production and manipulation
03.67.Ac Quantum algorithms, protocols, and simulations
03.67.Dd Quantum cryptography and communication security
42.79.Sz Optical communication systems, multiplexers, and demultiplexers

Random lasing from localized modes in strongly scattering systems consisting of macroporous titania monoliths infiltrated with dye solution

Shunsuke Murai, Koji Fujita, Junko Konishi, Kazuyuki Hirao, and Katsuhisa Tanaka

Appl. Phys. Lett. 97, 031118 (2010); http://dx.doi.org/10.1063/1.3464962 (3 pages) | Cited 2 times

Online Publication Date: 23 July 2010

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We have prepared random lasers that consist of macroporous titania monoliths infiltrated with dye solution and that operate close to light localization regime. When the excitation pulse energy exceeds a threshold, discrete spectral lines ascribed to laser oscillation appear on a featureless emission peak. No pulse-to-pulse variation was observed in the spectral positions of lasing lines, indicating that the lasing modes are localized in the medium. We demonstrated selective excitation of lasing modes by pumping at different positions on the sample.
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42.55.Rz Doped-insulator lasers and other solid state lasers
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
42.55.Mv Dye lasers

Continuous wave laser generation at 1064 nm in femtosecond laser inscribed Nd:YVO4 channel waveguides

Yang Tan, Feng Chen, J. R. Vázquez de Aldana, G. A. Torchia, A. Benayas, and D. Jaque

Appl. Phys. Lett. 97, 031119 (2010); http://dx.doi.org/10.1063/1.3467816 (3 pages) | Cited 9 times

Online Publication Date: 23 July 2010

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We report on continuous wave 1064 nm laser generation from an ultrafast laser inscribed neodymium-doped yttrium orthovanadate channel waveguide with pumping at 808 nm. Single-mode stable laser operations have been observed with pump powers at threshold as low as 14 mW and with laser slope efficiencies as high as 38.7%.
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42.55.Rz Doped-insulator lasers and other solid state lasers
42.60.By Design of specific laser systems
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.70.Hj Laser materials
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A resonance switch employing an explosive-emission cathode for high-power rf pulse compressors

O. A. Ivanov, V. A. Isaev, M. A. Lobaev, A. L. Vikharev, and J. L. Hirshfield

Appl. Phys. Lett. 97, 031501 (2010); http://dx.doi.org/10.1063/1.3466911 (3 pages)

Online Publication Date: 21 July 2010

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A switch for modulation of the Q-factor of a multimode storage resonator in a high-power active microwave pulse compressor is described. The switch was tested at low power level in a compressor operated at X band. A power gain of 19:1 in the compressed pulse with pulse duration of 40–50 ns was achieved. It is expected that the use of the switch as a component of an active microwave compressor may make it possible to produce compressed pulses at the gigawatt power level.
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84.40.-x Radiowave and microwave (including millimeter wave) technology
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Intrinsic geometric scattering probed by picosecond optoacoustics in a cylindrical cavity: Application to acoustic and optical characterizations of a single micron carbon fiber

D. Ségur, Y. Guillet, and B. Audoin

Appl. Phys. Lett. 97, 031901 (2010); http://dx.doi.org/10.1063/1.3464563 (3 pages) | Cited 1 time

Online Publication Date: 19 July 2010

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A picosecond pump-probe technique is used to reveal the optoacoustic response of a single micrometric carbon fiber. The signature of the intrinsic geometric scattering resulting from acoustic reflections at free surface of the cylindrical cavity is contained in the signals. The fiber transverse elastic properties and the fiber complex refractive index at 796 nm are measured nondestructively.
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78.20.Pa Photoacoustic effects
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
62.65.+k Acoustical properties of solids
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.20.D- Elasticity
78.47.J- Ultrafast spectroscopy (<1 psec)

Resonant slow modes in phononic crystal plates with periodic membranes

Che-Yuan Sun, Jin-Chen Hsu, and Tsung-Tsong Wu

Appl. Phys. Lett. 97, 031902 (2010); http://dx.doi.org/10.1063/1.3464955 (3 pages) | Cited 5 times

Online Publication Date: 19 July 2010

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We propose a distinct phononic-crystal plate structure that comprises periodic circular membranes and present the theoretical and experimental investigation of elastic-wave propagation in the structure. Owing to the weak rigidity of the membranes, there are slow propagating resonant modes appended to the band structure. These resonant modes can also be engineered to locate inside the complete band gap. The frequencies and group velocities can be tuned by changing the membrane thickness and radius. By utilizing the laser-ultrasonic technique, the resonance and slow group velocity are observed. The measured results are in good agreement with the theoretical predictions.
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63.20.-e Phonons in crystal lattices
46.40.Cd Mechanical wave propagation (including diffraction, scattering, and dispersion)
46.70.De Beams, plates, and shells
42.62.-b Laser applications

Pressure-temperature-La concentration three-dimensional phase diagram of La-modified PbTiO3 determined by Raman scattering

M. R. Joya and P. S. Pizani

Appl. Phys. Lett. 97, 031903 (2010); http://dx.doi.org/10.1063/1.3464971 (3 pages) | Cited 2 times

Online Publication Date: 19 July 2010

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A detailed Raman scattering study was performed on lanthanum-modified lead titanate (PLT) with compositions varying from pure PbTiO3 to La 20.0 at. %, for temperatures ranging from 8 K to temperatures above the Curie temperature and hydrostatic pressures up to 7.5 GPa. A complete La concentration-pressure-temperature three dimensional phase diagram was determined, by using the E(TO1) soft mode frequency as the main probe.
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77.80.bg Compositional effects
81.30.Dz Phase diagrams of other materials
62.50.-p High-pressure effects in solids and liquids
64.70.K- Solid-solid transitions
78.30.Am Elemental semiconductors and insulators
77.84.Cg PZT ceramics and other titanates

Reduced thermal resistance of the silicon-synthetic diamond composite substrates at elevated temperatures

V. Goyal, S. Subrina, D. L. Nika, and A. A. Balandin

Appl. Phys. Lett. 97, 031904 (2010); http://dx.doi.org/10.1063/1.3463455 (3 pages) | Cited 4 times

Online Publication Date: 19 July 2010

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The authors report results of experimental investigation of thermal conductivity of synthetic diamond-silicon composite substrates. Although composite substrates are more thermally resistive than silicon at room temperature they outperform conventional wafers at elevated temperatures owing to different thermal conductivity dependence on temperature. The crossover point is reached near ∼ 360 K and can be made even lower by tuning the polycrystalline-grain size, film thickness, and interface quality. The reduction of thermal resistance of composite wafers at temperatures, typical for operation of electronic chips, may lead to better thermal management and new phonon-engineered methods for the electron mobility enhancement.
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66.70.Lm Other systems such as ionic crystals, molecular crystals, nanotubes, etc.
72.20.Fr Low-field transport and mobility; piezoresistance

Alternating matter motion in photoinduced mass transport driven and enhanced by light polarization in amorphous chalcogenide films

M. L. Trunov, P. M. Lytvyn, and O. M. Dyachyns’ka

Appl. Phys. Lett. 97, 031905 (2010); http://dx.doi.org/10.1063/1.3467046 (3 pages) | Cited 4 times

Online Publication Date: 20 July 2010

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We present direct measurements of the kinetics of surface relief gratings (SRGs) formation in amorphous As20Se80 thin films observed in real time by in situ atomic force microscopy. SRGs are induced in different holographic schemes of recording using near band-gap light and enhanced additionally by light polarized orthogonally to the recording beams. We demonstrate that the direction of mass transport depends on the polarization of additional light and recording pattern and can be driven by their modulation. Additional light triggers a giant mass transport and accelerates SRG formation while increasing it in height up to the order of the film thickness.
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68.60.Bs Mechanical and acoustical properties
68.55.jd Thickness
68.35.Gy Mechanical properties; surface strains
68.37.Ps Atomic force microscopy (AFM)
68.35.bg Semiconductors
78.66.Jg Amorphous semiconductors; glasses
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