Ultra-broadband optical parametric chirped-pulse amplification by matching of both group-velocity and pulse-front

Ultra-broadband optical parametric chirped-pulse amplification is analyzed based the compensation of phase-mismatch, which is achieved by matching of both group-velocity and pulse-front between signal and idler by the combination of the noncollinear-phase-match and pulse-front-tilt. The results show exactly matching of both group-velocity and pulse-front is the important criterion for constructing an UBOPCPA. Its general model is developed, in which the group velocities, noncollinear angles. spatial walk-off angles, linear angular spectral dispersion coefficients and pulse-front tilted angles are suitably linked to each other. Finally, specific numerical calculations and simulations are presented for beta-barium borate OPCPA with type-1 noncollinear angularly dispersed geometry. (C) 2005 Elsevier B.V. All rights reserved.

Analysis of the modulation depth affected by the polarization orientation in polarization interference imaging spectrometers

The influence of the orientations of both polarizer and analyzer on modulation depth of spatially distributed interferograms for static polarization interference imaging spectrometer (SPIIS) is analyzed. A generally, theoretical relationship to determine the modulation depth of a SPIIS is derived. The special cases of maximum modulation depth (V = 1) and the minimum modulation depth (V = 0) are examined. Our results will provide a theoretical and practical guide for studying, developing and engineering polarization interference imaging spectrometers. (C) 2003 Elsevier B.V. All rights reserved.

A static polarization imaging spectrometer based on a Savart polariscope

This paper describes the design of an interference imaging spectrometer. A static Polarization Imaging Spectrometer (PIS) based on a single Savart polariscope has been developed. It produces the interferogram and target's image in the spatial domain which are recorded by using a two-dimensional (2D) CCD detector. Imaging lens localizes the interference fringes and target's image coincident with the plane of detector, thereby facilitating an extremely compact design. The spectrum of the input light is reconstructed through the Fourier-transform of the interferogram. The total optics is as small as 20 x 6 cm phi in size and the spectral resolution of the prototype system is 97.66 cm(-1) between 25,000 and 10, 000 cm(-1). The polarization interference imaging device has advantages of ultra-compact size, wide field of view, high throughput and without any moving parts. (C) 2002 Published by Elsevier Science B.V.

Real-time counting of single electron tunneling through a T-shaped double quantum dot system

Real-time detection of single electron tunneling through a T-shaped double quantum dot is simulated, based on a Monte Carlo scheme. The double dot is embedded in a dissipative environment and the presence of electrons on the double dot is detected with a nearby quantum point contact. We demonstrate directly the bunching behavior in electron transport, which leads eventually to a super-Poissonian noise. Particularly, in the context of full counting statistics, we investigate the essential difference between the dephasing mechanisms induced by the quantum point contact detection and the coupling to the external phonon bath. A number of intriguing noise features associated with various transport mechanisms are revealed.

The exciton-longitudinal-optical-phonon coupling in InGaN/GaN single quantum wells with various cap layer thicknesses

This paper studies the exciton-longitudinal-optical-phonon coupling in InGaN/GaN single quantum wells with various cap layer thicknesses by low temperature photoluminescence (PL) measurements With increasing cap layer thickness, the PL peak energy shifts to lower energy and the coupling strength between the exciton and longitudinal-optical (LO) phonon, described by Huang-Rhys factor, increases remarkably due to an enhancement of the internal electric field With increasing excitation intensity, the zero-phonon peak shows a blueshift and the Huang-Rhys factor decreases These results reveal that there is a large built-in electric field in the well layer and the exciton-LO phonon coupling is strongly affected by the thickness of the cap layer

THE EFFECT OF PASSIVATION OF BORON DOPANTS BY HYDROGEN IN NANO-CRYSTALLINE AND MICROCRYSTALLINE SILICON FILMS

It is well known that the value of room-temperature conductivity sigma(RT) of boron-doped silicon films is one order lower than that of phosphorus-doped silicon films, when they are deposited in an identical plasma-enhanced chemical vapour deposition system. We use surface acoustic wave and secondary-ion mass spectrometry techniques to measure the concentration of total and electrically active boron atoms. It is shown that only 0.7% of the total amount of incorporated boron is electrically active. This is evidence that hydrogen atoms can passivate substitutional B-Si bonds by forming the neutral B-H-Si complex. By irradiating the boron-doped samples with a low-energy electron beam, the neutral B-H-Si complex converts into electrically active B-Si bonds and the conductivity can be increased by about one order of magnitude, up to the same level as that of phosphorus-doped samples.

A NOVEL ODOR SENSOR COATED WITH A LIPID-MEMBRANE

In this paper, an interdigital electrode lipid film odour sensor (ILOS) is designed, fabricated and tested. It is made from a microfabricated chemiresistor coated with a synthetic multibilayer film. Nine odorants in gas phase at room temperature have been detected using the odour sensor. For most of the odorants, the relation between the response of the ILOS and odorant concentration obeys Stevens' power law, and there is a good correlation between the minimum odorant concentrations that give rise to a change of the sensor's conductance and human olfactory thresholds.

GROWTH OF GASB AND GAASSB IN THE SINGLE-PHASE REGION BY MOVPE

GaSb layers are grown on GaSb substrates; the effects of input partial pressure of trimethylantimony and the V/III ratio are studied. A model of the MOVPE phase diagram for the growth of GaSb and GaAsxSb1-x is developed which assumes thermodynamic equilibrium to be established at the solid-vapor interface.

35-PERCENT EFFICIENT NONCONCENTRATING NOVEL SILICON SOLAR-CELL

An energy conversion efficiency of 35% was obtained at 1-sun, air mass 1.5 for a novel silicon cell having an area of 2.3 X 2.3 mm2 . cell. The critical feature of the cell structure is the inclusion of local defect layers near a p-n junction. The local defect layers were proven to hold the key to achieving the exceptionally high efficiency of the novel cell fabricated via noncomplex processing.