1,790,180 research outputs found
Long period grating for 3-5 mu m quantum-well infra-red photodetectors
No full textBy considering all possible high order diffracted waves, the authors calculate the coupling efficiency of long period gratings for 3-5 mu m quantum-well infra-red photodetectors (QWIPs) on the basis of the modal expansion model (MEM). A large coupling efficiency for 3-5 mu m QWIPs has been demonstrated. This greatly reduces the difficulties in fabricating 3-5 mu m grating coupled QWIPs and opens the way to fabricate high performance 3-5 mu m and two colour QWIPs image arrays
Influence of growth parameters of frequency-radio plasma nitrogen source on extending emission wavelengths from 1.31 mu m to 1.55 mu m GaInNAs/GaAs quantum wells grown by molecular-beam epitaxy
No full textHigh (42.5%) indium content GaInNAs/GaAs quantum wells with room temperature emission wavelength from 1.3 mu m to 1.5 mu m range were successfully grown by Radio Frequency Plasma Nitrogen source assisted Molecular Beam Epitaxy. The growth parameters of plasma power and N-2 How rate were optimized systematically to improve the material quality. Photoluminescence and transmission electron microscopy measurements showed that the optical and crystal quality of the 1.54 mu m GaInNAs/GaAs QWs was kept as comparable as that in 1.31 mu m
1.58 mu m InGaAs quantum well laser on GaAs
No full textWe demonstrate the 1.58 mu m emission at room temperature from a metamorphic In0.6Ga0.4As quantum well laser grown on GaAs by molecular beam epitaxy. The large lattice mismatch was accommodated through growth of a linearly graded buffer layer to create a high quality virtual In0.32Ga0.68As substrate. Careful growth optimization ensured good optical and structural qualities. For a 1250x50 mu m(2) broad area laser, a minimum threshold current density of 490 A/cm(2) was achieved under pulsed operation. This result indicates that metamorphic InGaAs quantum wells can be an alternative approach for 1.55 mu m GaAs-based lasers. (C) 2007 American Institute of Physics
Recommended from our members
Laser-light-absorption studies at 1. 06. mu. m, 0. 53. mu. m, and 0. 35. mu. m wavelengths
No full textResults are presented of light absorption in a series of wavelength scaling experiments recently completed at LLNL. The Argus facility was used to do target studies at 1.06..mu..m, 0.53..mu..m and 0.35..mu..m. Box calorimeter scattered light measurements implied greatly improved laser light absorption for both high Z and low Z plasmas at laser wavelengths shorter than 1.06..mu..m. Furthermore, at the 0.35..mu..m laser wavelength, the inferred absorption is nearly 100% over a substantial range of incident laser intensities. Our results further show a dramatic decrease in the stimulated Brillouin scattered light at 0.35..mu..m relative to the values at 1.06..mu..m and 0.53..mu..m
Tm3+ and Nd3+ singly doped LiYF4 single crystals with 3-5 mu m mid-infrared luminescence
No full textMid-infrared (MIR) emissions of 2.4 and 3.5 mu m from Tm3+:LiYF4 single crystals attributed to H-3(4) -> H-3(5) and H-3(5) -> F-3(4) transitions as well as MIR emissions of 4.2, 4.3, and 4.5 mu m from Nd3+: LiYF4 lasers attributed to I-4(15/2) -> I-4(13/2), I-4(13/2) -> I-4(11/2), and I-4(11/2) -> I-4(9/2) transitions, respectively, are observed. LiYF4 single crystals possess high transmittance of over 85% in the 2.5-6 mu m range. The large emission cross-sections of Tm-doped crystals at 2.4 mu m (1.9 x 10(-20) cm(2)) and Nd-doped crystals at 4.2 mu m (0.84 x 10(-20) cm(2)) as well as the high rare-earth doping concentrations, excellent optical transmission, and chemical-physical properties of the resultant samples indicate that Nd3+ and Tm3+ singly doped crystals may be promising materials for application in MIR lasers
Recommended from our members
ARGUS disk-target experiments at 1. 06. mu. m, 0. 53. mu. m, 0. 35. mu. m
No full textWe report on ARGUS wavelength scaling experiments on disk targets at 1.06 ..mu..m, 0.53 ..mu..m, and 0.35 ..mu..m. Measurements were made of absorption, stimulated Brillouin and Raman scattering, and 3/2 harmonic light
THE WATER-VAPOR CONTINUUM AND SELECTIVE ABSORPTION IN THE 8 m TO 12 m AND 4 m TO 5 m WINDOWS AT TEMPERATURES FROM 311 K TO 363 K
No full textAuthor Institution: Optical Technology Division, NIST, Gaithersburg, MD 20899-8441, USAThe water-vapor continuum and selective absorption in the atmospheric windows strongly affect the radiative balance of the Earth. We have previously reported preliminary experimental results on the water-vapor continuum absorption} International Symposium on Molecular Spectroscopy, Columbus (2006)} between 8 \mu\mu^{-1}\mu\mu\mu\mum. Our continuum data extrapolated to room temperature are in reasonable agreement with the CKD continuum model}, 229, (1989)}. However, at high temperatures the CKD model provides values up to 50\%$ less than experimentally measured. While processing the spectra we have found that the intensities of several ro-vibrational lines in the HITRAN database need to be corrected. Also, at the relatively high vapor pressures mentioned above a self-induced pressure shift of several lines has been detected
Numerical study of strained InGaAs quantum well lasers emitting at 2.33 mu m using the eight-band model
No full textWe investigate the band structure of a compressively strained In(Ga)As/In(0.53)Ga(0.47)As quantum well (QW) on an InP substrate using the eight-band k.p theory. Aiming at the emission wavelength around 2.33 mu m, we discuss the influences of temperature, strain and well width on the band structure and on the emission wavelength of the QW. The wavelength increases with the increase of temperature, strain and well width. Furthermore, we design an InAs/In(0.53)Ga(0.47)As QW with a well width of 4.1 nm emitting at 2.33 mu m by optimizing the strain and the well width
Passive Q-switching in a diode-side-pumped Nd:YAG laser at 1.319 mu m
No full textWe demonstrated a passively Q-switched Nd:YAG laser operating at 1.319 mu m using a transmission-type single-wall carbon nanotube (SWCNT) as the saturable absorber. This is the first report on using SWCNT as a Q-switcher for 1.319 mu m Nd:YAG laser in a side-pumped configuration. A maximum output power of 780 mW was obtained with 1.15-mu s pulse duration and 42.7-kHz repetition rate. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE
Fabrication of Ge nano-dot heterojunction phototransistors for improved light detection at 1.55 mu m
No full textHeterojunction phototransistors (HPTs) with several Ge/Si nano-dot layers as the absorption region are fabricated to obtain improved light detectivity at 1.55 mu m. The HPT detectors are of n-p-n type with ten layers of Ge(8ML)/Si(45nm) incorporated in the base-collector junction and are grown by an ultrahigh-vacuum chemical-vapor deposition system. The detectors are operated with normal incidence. Because of the good quality of the grown material and fabrication process, the dark current is only 0.71pA/mu m(2) under 5 V bias and the break-down voltage is over 20 V. Compared to the positive-intrinsic-negative (PIN) reference detector with the same absorption layer, the responsivity is improved over 17 times for normal incidence at 1.55 mu m
- …
