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26 Jan 2009

Volume 94, Issue 4, Articles (04xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 94, 043101 (2009); http://dx.doi.org/10.1063/1.3070319 (3 pages)

Da-Yan Chen, Ming-Wang Shao, Liang Cheng, Xiu-Hua Wang, and Dorothy Duo-Duo Ma
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Lasing-induced reduction in core heating in high wall plug efficiency quantum cascade lasers

Anthony J. Hoffman, Phillip X. Braun, Matthew D. Escarra, Scott S. Howard, Kale J. Franz, Xiaojun Wang, Jenyu Fan, and Claire Gmachl

Appl. Phys. Lett. 94, 041101 (2009); http://dx.doi.org/10.1063/1.3073044 (3 pages)

Online Publication Date: 26 January 2009

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Quantum cascade (QC) laser core heating is a primary impediment to high device wall plug efficiency (WPE). Here, we demonstrate that efficient photon generation produces a quantifiable reduction in heating of the QC laser core temperature. By superimposing low duty cycle current pulses on a core-heating dc baseline, we observe the instantaneous threshold current and current efficiency evolution as the dc input is varied. From these measurements we recover the laser core temperature Tcore. Results agree well with calculations of Tcore based on measured thermal resistance and WPE. Using the same thermal model for a laser with negligible WPE, we show that the large WPE of the measured device—24% for an 80 K heat sink—results in a core temperature reduction of ∼ 15 K.
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42.55.Px Semiconductor lasers; laser diodes

Strong violet and green-yellow electroluminescence from silicon nitride thin films multiply implanted with Si ions

Z. H. Cen, T. P. Chen, L. Ding, Y. Liu, J. I. Wong, M. Yang, Z. Liu, W. P. Goh, F. R. Zhu, and S. Fung

Appl. Phys. Lett. 94, 041102 (2009); http://dx.doi.org/10.1063/1.3068002 (3 pages) | Cited 12 times

Online Publication Date: 26 January 2009

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Strong visible electroluminescence (EL) has been observed from a 30 nm silicon nitride thin film multiply implanted with Si ions and annealed at 1100 °C. The EL intensity shows a linear relationship with the current transport in the thin film at lower voltages, but a departure from the linear relationship with a quenching in the EL intensity is observed at higher voltages. The EL spectra show two primary EL bands including the predominant violet band at ∼ 3.0 eV (415 nm) and the strong green-yellow band at ∼ 2.2 eV (560 nm). Two weak bands including the ultraviolet band at ∼ 3.8 eV and the near infrared band at ∼ 1.45 eV emerge at high voltages. The evolution of each EL band with the voltage has been examined. The phenomena observed are explained, and the EL mechanisms are discussed.
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78.60.Fi Electroluminescence
78.66.Nk Insulators
61.80.Jh Ion radiation effects
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.up Other materials
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization

Reduced nonthermal rollover of wide-well GaInN light-emitting diodes

Markus Maier, Klaus Köhler, Michael Kunzer, Wilfried Pletschen, and Joachim Wagner

Appl. Phys. Lett. 94, 041103 (2009); http://dx.doi.org/10.1063/1.3073860 (3 pages) | Cited 16 times

Online Publication Date: 26 January 2009

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Nonthermal rollover (or efficiency droop) of the electroluminescence (EL) efficiency has been investigated for near-UV-emitting (AlGaIn)N single-well light-emitting diodes (LED) with varying GaInN well widths grown on substrates with different dislocation densities (DDs). For each DD the well width of the mesa-LEDs has been optimized for maximum EL efficiency at high operating currents. LEDs on freestanding GaN (DD 4×107 cm−2) with an 18 nm thick GaInN wide-well active region show the highest efficiency, and the output power-versus-current characteristic remains linear up to the highest pulsed current density of 750 A/cm2. In contrast, LEDs on sapphire grown with conventional low-temperature nucleation (DD 109 cm−2) exhibit the optimum well width at 3 nm and show significant nonthermal rollover.
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85.60.Jb Light-emitting devices
78.60.Fi Electroluminescence

Evanescent field at nanocorrugated dielectric surface

S. N. Volkov, A. E. Kaplan, and K. Miyazaki

Appl. Phys. Lett. 94, 041104 (2009); http://dx.doi.org/10.1063/1.3075055 (3 pages) | Cited 2 times

Online Publication Date: 26 January 2009

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We study coupling of laser pulses to an evanescent electric field at a nanocorrugated dielectric surface. We find that the local electric field is increased in the surface grooves, up to a factor of 2, compared to the incident field, thus providing a positive feedback for localized subthreshold ablation, and enabling the corrugation growth.
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79.20.Ds Laser-beam impact phenomena
81.65.-b Surface treatments

Time stretch enhanced recording oscilloscope

Shalabh Gupta and Bahram Jalali

Appl. Phys. Lett. 94, 041105 (2009); http://dx.doi.org/10.1063/1.3075057 (3 pages) | Cited 6 times

Online Publication Date: 26 January 2009

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Recording analog signals using photonic time-stretch technique in a mode which combines advantages of continuous signal capture, as in real-time analog-to-digital converters (ADCs), and very high bandwidth capability of (equivalent-time) sampling oscilloscopes, is proposed. It is shown that the eye diagrams of high speed serial data can be acquired at least 100 times faster than the fastest capture rates today. Unlike conventional sampling scopes, this technique can capture ultrafast dynamics of repetitive signals, nonrepetitive signals, and rare events. Experimentally, 45 Gbit/s data eye diagram measurement is demonstrated.
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07.07.Hj Display and recording equipment, oscilloscopes, TV cameras, etc.
84.30.-r Electronic circuits

Tunable broadband antireflection structures for silicon at terahertz frequency

Y. W. Chen, P. Y. Han, and X.-C. Zhang

Appl. Phys. Lett. 94, 041106 (2009); http://dx.doi.org/10.1063/1.3075059 (3 pages) | Cited 11 times

Online Publication Date: 26 January 2009

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We report enhanced transmission of broadband terahertz electromagnetic waves in the frequency range from 0.2 to 3.15 THz using silicon with micropyramid surface structures. We observe a maximum 89% reduction in reflectivity of terahertz power when the sample with 60-μm-period micropyramids is used, compared to a planar silicon substrate. By varying the period of micropyramid structures from 110 to 30 μm, the cutoff frequency of enhanced transmission is tuned from 0.74 to 2.93 THz and the bandwidth of enhancement increases from 0.91 to 3.15 THz, respectively.
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42.79.Wc Optical coatings
42.70.-a Optical materials

Spatially modulated fluorescence emission from moving particles

Peter Kiesel, Michael Bassler, Markus Beck, and Noble Johnson

Appl. Phys. Lett. 94, 041107 (2009); http://dx.doi.org/10.1063/1.3070536 (3 pages) | Cited 9 times

Online Publication Date: 27 January 2009

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An optical detection technique for a flow cytometer is described, which delivers high signal-to-noise discrimination without precision optics to enable a flow cytometer that can combine high performance, robustness, compactness, low cost, and ease of use. The enabling technique is termed “spatially modulated emission” and generates a time-dependent signal as a continuously fluorescing bioparticle traverses a predefined pattern for optical transmission. Correlating the detected signal with the known pattern achieves high discrimination of the particle signal from background noise. The technique is demonstrated with measurements of fluorescent beads flowing through a microfluidic chip.
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87.80.Ek Mechanical and micromechanical techniques
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
87.15.M- Spectra of biomolecules
47.85.Np Fluidics
47.63.-b Biological fluid dynamics
87.17.-d Cell processes

Electrowetting retroreflectors: Scalable and wide-spectrum modulation between corner cube and scattering reflection

M. K. Kilaru, B. Cumby, and J. Heikenfeld

Appl. Phys. Lett. 94, 041108 (2009); http://dx.doi.org/10.1063/1.3073840 (3 pages) | Cited 2 times

Online Publication Date: 27 January 2009

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Corner cube and spherical retroreflectors are ubiquitous in conspicuity and range-finding applications since they reflect light back to the illumination source with unmatched efficiency. We report here a switchable electrowetting retroreflector platform that provides multiple novel features, including (a) using <0.5 μJ/cm2 electrical energy to switch from a light scattering state, (b) low loss and wide spectrum as limited only by the absorption spectrum of water, (c) use of ultrasimple self-assembly of 103–105 liquid lenslets/in.2 on a polymer/Al corner-cube substrate, and (d) change in retroreflected irradiance of >10:1 over a ±30° field of view.
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42.79.Fm Reflectors, beam splitters, and deflectors
42.25.Gy Edge and boundary effects; reflection and refraction
42.25.Fx Diffraction and scattering

High-efficiency staggered 530 nm InGaN/InGaN/GaN quantum-well light-emitting diodes

Seoung-Hwan Park, Doyeol Ahn, and Jong-Wook Kim

Appl. Phys. Lett. 94, 041109 (2009); http://dx.doi.org/10.1063/1.3075853 (3 pages) | Cited 28 times

Online Publication Date: 27 January 2009

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Optical properties of staggered 530 nm InGaN/InGaN/GaN quantum-well (QW) light-emitting-diodes are investigated using the multiband effective mass theory. These results are compared with those of conventional 530 nm InGaN/GaN QW structures. A staggered InGaN/InGaN/GaN QW structure is shown to have much larger spontaneous emission than a conventional InGaN/GaN QW structure. This can be explained by the fact that a staggered QW structure has much larger matrix element than a conventional QW structure because a spatial separation between electron and hole wave functions is substantially reduced with the inclusion of a staggered InGaN layer. A staggered QW structure shows that the peak position at a high carrier density (530 nm) is similar to that at a noninjection level.
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85.60.Jb Light-emitting devices

The role of p-doping in the gain dynamics of InAs/GaAs quantum dots at low temperature

Valentina Cesari, Wolfgang Langbein, and Paola Borri

Appl. Phys. Lett. 94, 041110 (2009); http://dx.doi.org/10.1063/1.3075855 (3 pages) | Cited 5 times

Online Publication Date: 27 January 2009

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We measured the gain dynamics of the ground-state transition at 20 K in an undoped and identically fabricated p-doped InAs/GaAs quantum-dot amplifier. The dynamics in the doped device is dominated by a very short ( ∼ 0.1 ps) and a very long ( ∼ 300 ps) time constant. These were attributed to hole and electron dynamics, respectively, and quantitatively described by a microstate model. By comparing the dynamics for the same modal gain in the two devices, the gain recovery was initially faster in the p-doped sample, attributed to ultrafast hole-hole scattering, but slower at later times due to the lack of an electron reservoir.
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42.55.Px Semiconductor lasers; laser diodes
73.63.Kv Quantum dots
73.21.La Quantum dots
61.72.uj III-V and II-VI semiconductors
78.47.J- Ultrafast spectroscopy (<1 psec)
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping

Robust organic lasers comprising glassy-cholesteric pentafluorene doped with a red-emitting oligofluorene

Simon K. H. Wei, Shaw H. Chen, Ksenia Dolgaleva, Svetlana G. Lukishova, and Robert W. Boyd

Appl. Phys. Lett. 94, 041111 (2009); http://dx.doi.org/10.1063/1.3073713 (3 pages) | Cited 7 times

Online Publication Date: 28 January 2009

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Doped with a red-emitting oligofluorene, fluid and glassy cholesteric liquid crystal (CLC) films are characterized by similar lasing thresholds and efficiencies. With picosecond excitations the output from a glassy CLC laser is temporally stable, but that from a fluid CLC laser decays with time. The difference in stability is attributable to external perturbations on supramolecular structure in the fluid but not the solid state, such as heating through optical pumping, light-induced pitch dilation, and laser-induced flow.
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42.55.-f Lasers

Role of carrier reservoirs on the slow phase recovery of quantum dot semiconductor optical amplifiers

J. Kim, C. Meuer, D. Bimberg, and G. Eisenstein

Appl. Phys. Lett. 94, 041112 (2009); http://dx.doi.org/10.1063/1.3073715 (3 pages) | Cited 14 times

Online Publication Date: 28 January 2009

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The gain and phase recovery dynamics of quantum-dot (QD) semiconductor optical amplifiers are calculated, including all the optical transitions involved in successive carrier recovery processes. The carrier recovery dynamics of inhomogeneously broadened QDs is simulated by solving 1088 coupled rate equations. The respective contributions of QD states and quantum-well carrier reservoirs to the gain and phase changes are identified both temporally and spectrally. We show that the slow phase recovery component of the QD ground state is induced by the slow carrier dynamics of the carrier reservoir due to a slowly varying line shape function of the refractive index change.
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42.55.Px Semiconductor lasers; laser diodes

Control of liquid crystal pretilt angle by anchoring competition of the stacked alignment layers

You-Jin Lee, Jin Seog Gwag, Young-Ki Kim, Soo In Jo, Seung-Gon Kang, Young Ran Park, and Jae-Hoon Kim

Appl. Phys. Lett. 94, 041113 (2009); http://dx.doi.org/10.1063/1.3068003 (3 pages) | Cited 17 times

Online Publication Date: 28 January 2009

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We proposed a method to control the pretilt angle of liquid crystals by stacking of a vertical alignment layer on a planar alignment layer. The pretilt angle can be controlled over the full range (0°–90°) depending on the thickness of the vertical alignment layer. We also proposed a numerical model to describe the physical mechanism based on the anchoring competition between liquid crystal, planar, and vertical polyimide alignment layers.
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61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order
61.30.Vx Polymer liquid crystals
61.20.Gy Theory and models of liquid structure

Step well quantum cascade laser emitting at 3 THz

Giacomo Scalari, Maria I. Amanti, Milan Fischer, Romain Terazzi, Christoph Walther, Mattias Beck, and Jérôme Faist

Appl. Phys. Lett. 94, 041114 (2009); http://dx.doi.org/10.1063/1.3068496 (3 pages) | Cited 14 times

Online Publication Date: 28 January 2009

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A quantum cascade laser based on a three well active module and emitting at 3 THz is demonstrated. The optical transition is vertical in real space and localized in an Al0.03Ga0.97As quantum well. Maximum operating temperature of 123 K in pulsed mode is reported, with threshold current densities as low as 110 A/cm2 at 10 K and 175 A/cm2 at 100 K. High slope efficiency values testify the good internal quantum efficiency of the structure.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
73.21.Fg Quantum wells

An algorithm to sculpt photon dispersion in a subwavelength nanostructure

Feng Zhang, Kito S. Holliday, Paul E. Lammert, and Vincent H. Crespi

Appl. Phys. Lett. 94, 041115 (2009); http://dx.doi.org/10.1063/1.3072594 (3 pages) | Cited 1 time

Online Publication Date: 28 January 2009

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We introduce a method of gradient-based optimization that continuously deforms a periodic dielectric distribution to generate photonic structures that possess any desired figure of merit expressible in terms of the electromagnetic eigenmodes. As an example, we generate forbidden regions between specified bands at extremely low dielectric contrast.
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42.70.Qs Photonic bandgap materials
02.60.Pn Numerical optimization
77.22.Ch Permittivity (dielectric function)

Effects of organic film morphology on the formation of Rb clusters on surface coatings in alkali metal vapor cells

D. M. Rampulla, N. Oncel, E. Abelev, Y. W. Yi, S. Knappe, and S. L. Bernasek

Appl. Phys. Lett. 94, 041116 (2009); http://dx.doi.org/10.1063/1.3073711 (3 pages) | Cited 7 times

Online Publication Date: 29 January 2009

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Surface relaxation rates differ for spin-polarized alkali atoms interacting with monolayer or bilayer octadecyltrichlorosilane (OTS) coatings. The morphology and composition of Rb vapor-exposed films of OTS have been studied with atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS). On OTS monolayers, numerous small (<500 nm wide) Rb containing islands nucleate at the boundaries of the ∼ 1–2 μm wide organic domains. On OTS bilayers, singular large ( ∼ 3 μm wide) Rb containing islands were found. Alkali island formation mediated by surface structure could affect the antirelaxation behavior of organic coatings used in atomic magnetometer cells.
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68.55.J- Morphology of films
68.55.aj Insulators
79.60.Bm Clean metal, semiconductor, and insulator surfaces

Rapid efficiency roll-off in high-quality green light-emitting diodes on freestanding GaN substrates

Y. Yang, X. A. Cao, and C. H. Yan

Appl. Phys. Lett. 94, 041117 (2009); http://dx.doi.org/10.1063/1.3077017 (3 pages) | Cited 10 times

Online Publication Date: 29 January 2009

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InGaN/GaN multiple-quantum-well green light-emitting diodes (LEDs) were grown on freestanding GaN and sapphire substrates. The density of microstructural defects in the LED on GaN was substantially reduced, leading to a significant reduction in defect-assisted tunneling currents and an improved injection efficiency under low bias. The LED on GaN outperformed the LED on sapphire at low injection currents and exhibited a ∼ 65% peak internal quantum efficiency. However, it suffered from even more dramatic efficiency roll-off, which occurs at a current density as low as 0.3 A/cm2. This behavior is explained as the combined result of efficient current injection and significant carrier overflow in a high-quality LED.
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85.60.Jb Light-emitting devices
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)

Tunnel junction transistor laser

M. Feng, N. Holonyak, Jr., H. W. Then, C. H. Wu, and G. Walter

Appl. Phys. Lett. 94, 041118 (2009); http://dx.doi.org/10.1063/1.3077020 (3 pages) | Cited 9 times

Online Publication Date: 29 January 2009

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A transistor laser with a tunnel junction collector is demonstrated. Its optical output is sensitive to third terminal voltage control owing to the electron tunneling (photon-assisted or not assisted) from the base to collector, which acts in further support of resupply of holes for recombination in addition to the usual base Ohmic current, IB. Collector tunneling enhances laser operation even under a weak collector junction field and quenches it under a strong reverse-biased field. The sensitivity of the tunnel junction transistor laser to voltage control enables the tunnel junction transistor laser to be directly modulated by both current and voltage control.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Erbium-ytterbium codoped waveguide amplifier fabricated with solution-processable complex

Cong Chen, Dan Zhang, Tong Li, Daming Zhang, Limei Song, and Zhen Zhen

Appl. Phys. Lett. 94, 041119 (2009); http://dx.doi.org/10.1063/1.3077152 (3 pages) | Cited 6 times

Online Publication Date: 29 January 2009

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A solution-processable erbium-ytterbium codoped complex is synthesized. The absorption and photoluminescence spectra of the complex are observed. The full width at half maximum of the emission spectrum is 80 nm around 1530 nm. A structure of embedded waveguide with the complex as core layer is designed. With an input signal power of 0.3 mW, an optical gain of 5.2 dB at a wavelength of 1550 nm is obtained in a 15-mm-long waveguide when the cladding layer is SU-8. When the cladding layer is polymethyl methacrylate, an optical gain of 6.5 dB is obtained in a 12-mm-long waveguide with an input signal power of 1 mW.
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42.79.Gn Optical waveguides and couplers
78.55.Kz Solid organic materials
78.30.Jw Organic compounds, polymers

Electrodeposition of single-crystalline silver pearl chains

Zhe Wu, Hong-Min Li, Xiang Xiong, Guo-Bin Ma, Mu Wang, Ru-Wen Peng, and Nai-Ben Ming

Appl. Phys. Lett. 94, 041120 (2009); http://dx.doi.org/10.1063/1.3072607 (3 pages) | Cited 1 time

Online Publication Date: 29 January 2009

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We report in this letter the fabrication of unique single-crystalline silver filaments with periodic, pearl-chain-like structures by electrodeposition without using any templates, surfactants, and additives. Fourier transform infrared spectroscopy, infrared focus-plane-array imaging, and numerical simulations demonstrate that the excited surface waves may sustain on the silver “pearl chains” in midinfrared range. Based on the propagation features of surface waves on the silver filaments, we suggest that such a structure can be applied for light transmission in midinfrared range.
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81.15.Pq Electrodeposition, electroplating
78.30.Er Solid metals and alloys

Silicon-on-insulator photoconductors for ultrasonic vibration detection with laser speckle

Jonathan Bessette, Ashifi Gogo, and Elsa Garmire

Appl. Phys. Lett. 94, 041121 (2009); http://dx.doi.org/10.1063/1.3077159 (3 pages)

Online Publication Date: 29 January 2009

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Speckle-sized photoconductive silicon-on-insulator mesas have been designed to optically detect surface vibrations at frequencies extending into the megahertz range. When a single diode laser beam reflects off a vibrating surface as a moving speckle pattern, the photoconductive mesas can detect lateral speckle motion. The capability of noncontact, nondestructive testing via laser-induced ultrasonic vibrations was demonstrated using these photoconductive silicon mesas in a simple and rugged single-monitoring-beam configuration.
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07.10.-h Mechanical instruments and equipment
81.70.Cv Nondestructive testing: ultrasonic testing, photoacoustic testing
42.30.Ms Speckle and moiré patterns

Fabrication and characterization of three-dimensional all metallic photonic crystals for near infrared applications

Yu-Lin Yang, Fu-Ju Hou, Shich-Chuan Wu, Wen-Hsien Huang, Ming-Chih Lai, and Yang-Tung Huang

Appl. Phys. Lett. 94, 041122 (2009); http://dx.doi.org/10.1063/1.3075056 (3 pages) | Cited 4 times

Online Publication Date: 29 January 2009

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Three-dimensional all metallic photonic crystals with a feature size of 0.20 μm were fabricated using electron-beam lithography with the photoresist of hydrogen silesquioxane. This process method has high compatibility with the fabrication of damascene copper interconnections and also simplifies the whole process flow. The dependence of the complete photonic band gaps on polarization was experimentally observed and compared with the simulation results. The band edge for the four-layer lattice was found at a wavelength of around 0.80 μm in normal incidence.
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42.70.Qs Photonic bandgap materials
42.82.Cr Fabrication techniques; lithography, pattern transfer
42.82.Ds Interconnects, including holographic interconnects
42.25.Ja Polarization

Ultrafast optofluidic gain switch based on conjugated polymer in femtosecond laser fabricated microchannels

Krishna Chaitanya Vishnubhatla, Jenny Clark, Guglielmo Lanzani, Roberta Ramponi, Roberto Osellame, and Tersilla Virgili

Appl. Phys. Lett. 94, 041123 (2009); http://dx.doi.org/10.1063/1.3076120 (3 pages) | Cited 17 times

Online Publication Date: 30 January 2009

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We report on an optofluidic gain switch based on polydioctylfluorene solution in a femtosecond laser fabricated microchannel. The solution provides a stimulated emission cross section of the order of 10−16 cm2. Depending on the good isolation of polymeric chains we obtain ultrafast gain switching with time constants below 150 fs and high on/off ratios (up to 100%) in a broad spectral region (450–500 nm). This enables potential modulation rates well in the terahertz range. The enhanced optofluidic functionalities combined with the flexibility of femtosecond laser micromachining pave the way to an innovative class of optical devices easily integratable in complex systems.
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07.10.Cm Micromechanical devices and systems
47.85.Np Fluidics

Silver-clad nitride semiconductor laser diode

David Bour, Christopher Chua, Zhihong Yang, Mark Teepe, and Noble Johnson

Appl. Phys. Lett. 94, 041124 (2009); http://dx.doi.org/10.1063/1.3077012 (3 pages) | Cited 1 time

Online Publication Date: 30 January 2009

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An edge-emitting laser diode is described in which the epitaxial upper cladding layer is replaced with a metal contact selected for its optical as well as electrical properties. The structure is demonstrated with an In0.1Ga0.9N multiple-quantum-well laser diode operating at 412 nm with silver rather than the typical p-type AlGaN for the upper cladding. Silver is effective as a cladding layer because of its very low index of refraction at the lasing wavelength, so that the guided optical mode exhibits minimal penetration into the silver. Eliminating the epitaxial upper cladding layer reduces thermal degradation of the InGaN multiple-quantum-well active layer.
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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.)

Interferences in photodetachment of a triatomic negative ion

A. Afaq, Iftikhar Ahmad, M. A. Ahmad, A. Rashid, B. A. Tahir, and Muhammad Tahir Hussain

Appl. Phys. Lett. 94, 041125 (2009); http://dx.doi.org/10.1063/1.3074372 (3 pages) | Cited 6 times

Online Publication Date: 30 January 2009

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The photodetachment of a triatomic negative ion is studied and the detached-electron wave function is obtained as a superposition of coherent waves originating from each atom of the system. The photodetached electron flux is evaluated on a screen placed at a large distance from the system, which displays strong interferences. A simple analytical formula is also obtained for the total photodetachment cross section. The formula approaches one time the cross sections for the one-center and two-center systems in the high photon energy limits. Also it approaches three times the cross section for one-center system in the low photon energy limits.
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32.80.Gc Photodetachment of atomic negative ions
31.15.-p Calculations and mathematical techniques in atomic and molecular physics
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