Now showing items 91-100 of 169
Ultrafast acoustics for imaging at the nanoscale
(IOP Publishing Ltd, 2007-12-01)
In this paper we present a series of experiments which show that 2-D and possibly 3-D imaging with sub-micron resolution is possible by means of ultrafast acoustic techniques. Optical pulses from a Ti:sapphire laser are ...
Density and temperature dependence of carrier dynamics in self-organized InGaAs quantum dots
(IOP Publishing Ltd, 2005-07-07)
We have used two- and three-pulse femtosecond differential transmission spectroscopy to study the dependence of quantum dot carrier dynamics on temperature. At low temperatures and densities, the rates for relaxation between ...
Novel use of resonant tunneling structures for optical and IR modulators
(Elsevier, 1989)
The basic concepts and some preliminary calculations are presented showing the feasibility of high speed optical and infrared modulators based on resonant tunneling structures. A modulator based on a conventional resonant ...
Generation and measurement of >10 8 intensity contrast ratio in a relativistic kHz chirped-pulse amplified laser
(Springer-Verlag, 2005-08)
We report on the generation and measurement of a > 10 8 contrast ratio between main pulse and amplified spontaneous emission (ASE) from a relativistic kHz chirped-pulse amplified laser. We have enhanced the ASE contrast ...
On the design of experiments for the study of relativistic nonlinear optics in the limit of single-cycle pulse duration and single-wavelength spot size
(Nauka/Interperiodica; MAIK "Nauka/Interperiodica" ; Springer Science+Business Media, 2002-01)
We propose a set of experiments with the aim of studying for the first time relativistic nonlinear optics in the fundamental limits of single-cycle pulse duration and single-wavelength spot size. The laser system that makes ...
Design, fabrication and operation of a hot electron resonant tunneling transistor
(Elsevier, 1989-12)
Transistors employing resonant tunneling injection of hot electrons into a thin quantum well base region have been fabricated. The base region in these transistors is formed by a narrow bandgap material like InGaAs so that ...
Phase-matched enhancements of high-harmonic soft X-rays by adaptive wave-front control with a genetic algorithm
(Springer-Verlag, 2004-02)
We demonstrate the enhancement of high-harmonic soft-X-ray generation by adaptive wave-front control of a 745-nm Ti:sapphire laser by use of a 59-channel membrane deformable mirror, combined with a genetic algorithm, for ...
Ultrafast ytterbium-doped bulk lasers and laser amplifiers
(Springer-Verlag, 1999-07)
We review recent achievements with ultrafast bulk lasers and amplifiers based on Yb:YAG and Yb:glass. Special attention is paid to those aspects of the quasi-three-level nature of these gain media that are important for ...
The relation of dominant deep levels in MOCVD AlxGa1-xAs with growth conditions
(Elsevier, 1984-09-01)
High quality undoped AlxGa1-xAs (0 x [les] 0.4) has been investigated by transient capacitance, deep level transient spectroscopy and photoluminescence measurement techniques. The crystals were intentionally grown under ...
Absorption and photoluminescence studies of the temperature dependence of exciton life time in lattice-matched and strained quantum well systems
(Elsevier, 1987)
We present systematic studies of the temperature dependence of linewidths and lifetimes of excitonic transitions in quantum wells grown by molecular beam epitaxy using both photoluminescence(PL) and optical absorption. The ...