http://www.sciencearchived.com Science News, Articles and Vacancies Thu, 11 Mar 2010 17:49:35 +0000 http://wordpress.org/?v=2.3.2 en http://www.sciencearchived.com/efficient-low-power-terahertz-generation-via-on-chip-triply-resonant-nonlinear-frequency-mixing/ http://www.sciencearchived.com/efficient-low-power-terahertz-generation-via-on-chip-triply-resonant-nonlinear-frequency-mixing/#comments Thu, 11 Mar 2010 17:49:35 +0000 admin 06a828304fe3628b3925776e1bd948f9_dc17d9039552598e8f815d33cc6664a0 In this letter, we show theoretically how the light-confining properties of triply-resonant photonic resonators can be tailored to enable dramatic enhancements of the conversion efficiency of terahertz (THz) generation via nonlinear frequency down-conversion processes. Using detailed numerical calcu ... [Appl. Phys. Lett. 96, 101110 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/efficient-low-power-terahertz-generation-via-on-chip-triply-resonant-nonlinear-frequency-mixing/feed/ http://www.sciencearchived.com/doping-tunable-resonance-toward-electrically-tunable-mid-infrared-metamaterials/ http://www.sciencearchived.com/doping-tunable-resonance-toward-electrically-tunable-mid-infrared-metamaterials/#comments Thu, 11 Mar 2010 17:49:35 +0000 admin 06a828304fe3628b3925776e1bd948f9_e37359e6fc58b9bb4c387ecbb2522730 We demonstrate metamaterials at the mid-infrared (mid-IR) wavelengths (812 [mu]m) that can be widely tuned by doping in adjacent semiconductor epilayers. The metamaterials are based on metallic split ring resonators (SRRs) fabricated on doped indium antimonide (InSb). Finite integral time-domain si ... [Appl. Phys. Lett. 96, 101111 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/doping-tunable-resonance-toward-electrically-tunable-mid-infrared-metamaterials/feed/ http://www.sciencearchived.com/high-responsivity-and-internal-gain-mechanisms-in-au-znmgo-schottky-photodiodes/ http://www.sciencearchived.com/high-responsivity-and-internal-gain-mechanisms-in-au-znmgo-schottky-photodiodes/#comments Thu, 11 Mar 2010 17:49:35 +0000 admin 06a828304fe3628b3925776e1bd948f9_85244430e1fb52a0b1ee00c2a29a5d4c Schottky photodiodes based on Au-ZnMgO/sapphire are demonstrated covering the spectral region from 3.35 to 3.48 eV, with UV/VIS rejection ratios up to ~10 and responsivities as high as 185 A/W. Both the rejection ratio and the responsivity are shown to be largely enhanced by the presence of an inter ... [Appl. Phys. Lett. 96, 101112 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/high-responsivity-and-internal-gain-mechanisms-in-au-znmgo-schottky-photodiodes/feed/ http://www.sciencearchived.com/dielectrophoretically-tuneable-optical-waveguides-using-nanoparticles-in-microfluidics/ http://www.sciencearchived.com/dielectrophoretically-tuneable-optical-waveguides-using-nanoparticles-in-microfluidics/#comments Thu, 11 Mar 2010 17:49:35 +0000 admin 06a828304fe3628b3925776e1bd948f9_a224ae0e4e6cfb484c4dfc40ed928ea6 We present a tuneable optical waveguide using dielectrophoretically controlled nanoparticles in microfluidics. Silicon dioxide nanoparticles of different sizes in de-ionized water are channelled through a microfluidic system. An array of microelectrodes generates the dielectrophoretic force to funne ... [Appl. Phys. Lett. 96, 101108 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/dielectrophoretically-tuneable-optical-waveguides-using-nanoparticles-in-microfluidics/feed/ http://www.sciencearchived.com/electronic-and-optical-properties-of-cdzno-quantum-well-structures-with-electric-field-and-polarization-effects/ http://www.sciencearchived.com/electronic-and-optical-properties-of-cdzno-quantum-well-structures-with-electric-field-and-polarization-effects/#comments Thu, 11 Mar 2010 17:49:35 +0000 admin 06a828304fe3628b3925776e1bd948f9_b0da44538d162af09dee7e15503bf48f Electronic, optical, and electrical properties of CdZnO/MgZnO quantum well (QW) structures, considering internal field and polarization effect, are investigated by using many-body theory. The CdZnO/MgZnO QW structure with higher Cd composition, which has deeper and stronger confinement, is found to ... [Appl. Phys. Lett. 96, 101113 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/electronic-and-optical-properties-of-cdzno-quantum-well-structures-with-electric-field-and-polarization-effects/feed/ http://www.sciencearchived.com/high-performance-tunnel-injection-quantum-dot-comb-laser/ http://www.sciencearchived.com/high-performance-tunnel-injection-quantum-dot-comb-laser/#comments Thu, 11 Mar 2010 17:49:35 +0000 admin 06a828304fe3628b3925776e1bd948f9_fc839932991bf0a56312df488af60c0d A high-speed multiwavelength quantum dot comb laser, grown by molecular beam epitaxy, is demonstrated. The device is characterized with a 75.9 nm (full width at half maximum) and a 91.4 nm (Delta) wide lasing spectrum. There are 105 and 185 simultaneously emitted longitudinal modes with a maximum ch ... [Appl. Phys. Lett. 96, 101107 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/high-performance-tunnel-injection-quantum-dot-comb-laser/feed/ http://www.sciencearchived.com/super-reflection-and-cloaking-based-on-zero-index-metamaterial/ http://www.sciencearchived.com/super-reflection-and-cloaking-based-on-zero-index-metamaterial/#comments Thu, 11 Mar 2010 17:49:35 +0000 admin 06a828304fe3628b3925776e1bd948f9_6085a71a75f311364a1199ca82cf416b A zero index metamaterial (ZIM) can be utilized to block wave (super-reflection) or conceal objects completely (cloaking). The super-reflection device can be realized by a Mu zero (Epsilon zero) metamaterial with a perfect electric (magnetic) conductor inclusion of arbitrary shape and size for a tra ... [Appl. Phys. Lett. 96, 101109 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/super-reflection-and-cloaking-based-on-zero-index-metamaterial/feed/ http://www.sciencearchived.com/phase-locked-arrays-of-surface-emitting-terahertz-quantum-cascade-lasers/ http://www.sciencearchived.com/phase-locked-arrays-of-surface-emitting-terahertz-quantum-cascade-lasers/#comments Thu, 11 Mar 2010 17:49:35 +0000 admin 06a828304fe3628b3925776e1bd948f9_b4d61c213a3150573abd9099df7b2240 We report the demonstration of phase-locked arrays of surface-emitting distributed-feedback (DFB) terahertz quantum-cascade lasers with single-mode operations. Carefully designed phase sector locks several surface-emitting DFB laser ridges in-phase, creating tighter beam-patterns along the phased-ar ... [Appl. Phys. Lett. 96, 101106 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/phase-locked-arrays-of-surface-emitting-terahertz-quantum-cascade-lasers/feed/ http://www.sciencearchived.com/an-electrically-injected-quantum-dot-spin-polarized-single-photon-source/ http://www.sciencearchived.com/an-electrically-injected-quantum-dot-spin-polarized-single-photon-source/#comments Wed, 10 Mar 2010 22:03:08 +0000 admin 06a828304fe3628b3925776e1bd948f9_bb97c35ba83a7c51d39eb6422ea673da The characteristics of an electrically injected spin polarized single photon source have been investigated. The GaAs-based microcavity diode consists of a single InAs/GaAs self-organized quantum dot as the single photon source and a MnAs/AlGaAs Schottky tunnel barrier for the ferromagnetic contact t ... [Appl. Phys. Lett. 96, 101105 (2010)] published Tue Mar 9, 2010.]]> http://www.sciencearchived.com/an-electrically-injected-quantum-dot-spin-polarized-single-photon-source/feed/ http://www.sciencearchived.com/uniform-field-transverse-electroreflectance-using-a-mode-locked-laser-and-a-radio-frequency-bias/ http://www.sciencearchived.com/uniform-field-transverse-electroreflectance-using-a-mode-locked-laser-and-a-radio-frequency-bias/#comments Wed, 10 Mar 2010 22:03:08 +0000 admin 06a828304fe3628b3925776e1bd948f9_323f1e295e3bdc96f19585e2dbbf629e We describe a technique for transverse electroreflectance that uses broadband optical pulses from a mode-locked laser and a rapidly oscillating bias with a frequency near half the laser repetition rate. Since the electrodes are electrically isolated from the sample, highly nonuniform trap-enhanced f ... [Appl. Phys. Lett. 96, 101104 (2010)] published Tue Mar 9, 2010.]]> http://www.sciencearchived.com/uniform-field-transverse-electroreflectance-using-a-mode-locked-laser-and-a-radio-frequency-bias/feed/