摘要:

Proton bombardment is used to increase the response speed of InP optoelectronic switches. Photoconductivity measurements indicate response times following bombardment of <100 ps, with the electron mobility estimated to be ⩾600 cm2/Vs. This mobility is over an order of magnitude larger than that observed in similar high‐resistivity devices of comparable speed fabricated in germanium or silicon‐on‐sapphire.

ISSN:0003-6951    

DOI:10.1063/1.93143

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

We report here the demonstration of several new optical oscillator configurations including a unidirectional ring oscillator and a self‐pumped phase conjugate mirror. The gain medium is BaTiO3, pumped by a 632.8‐nm He‐Ne laser at power levels down to 50 &mgr;W.

ISSN:0003-6951    

DOI:10.1063/1.93144

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The small‐signal modulation response of semiconductor lasers with a very small mirror reflectivity is analyzed. Superluminescent effects inside the laser cavity provide yet another mechanism for damping relaxation oscillation resonance. These results can serve as useful guides in designing high frequency semiconductor lasers.

ISSN:0003-6951    

DOI:10.1063/1.93145

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Radiometric levitation of a 20‐&mgr;‐diam dye‐impregnated glycerol sphere has been observed at intensities as low as ∼1 W/cm2in air at 30 Torr. The levitation has been effected on both strongly absorbing spheres in the direction of the light and weakly absorbing spheres in the opposite sense. Both strongly and weakly absorbing spheres are found to laterally seek an intensity minimum. Consequently particles were stably held in the focused beam of an Ar+laser (4880 A˚) operating in the TEM*01(doughnut) mode.

ISSN:0003-6951    

DOI:10.1063/1.93146

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Free‐carrier‐induced optical nonlinearities were studied, via four‐wave mixing, inn‐InSb as a function of the frequency difference &Dgr;&ohgr;, between two CO2laser beams. The third‐order nonlinear susceptibility increases by more than an order of magnitude as &Dgr;&ohgr;→0. This effect is ascribed to electron temperature fluctuations produced by the nonlinear optical interactions. An energy relaxation time of 3–4 ps is inferred for the highly excited electron gas. Studies of the frequency dependence of the nonlinear susceptibility may provide a new technique for measuring fast relaxation times in semiconductors.

ISSN:0003-6951    

DOI:10.1063/1.93147

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Results obtained with the University of California, Irvine gas‐puffZ‐pinch experiment are described for deuterium and deuterium‐argon mixtures. This experiment utilizes a hollow cylindrical gas puff injected between electrodes driven by a 4.8‐kJ capacitor bank. Various gas compositions have been tested, including pure deuterium, 90% D2‐10% Ar, and up to 10% D2‐90% Ar. We have observed the stages of collapse and its rate, electron density at the pinch, neutron yield, and the time dependence of x‐ray and neutron emission. When a 90% D2‐10% Ar mixture is injected, the plasma annulus is observed to separate into two columns which implode concentrically.

ISSN:0003-6951    

DOI:10.1063/1.93148

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

An explosive generator driven dense plasma focus is simulated numerically using a magnetohydrodynamic model which includes thermal conduction, resistive diffusion, and radiation in addition to the Lorentz force and shock hydrodynamics. It is shown that the dominant heating mechanism is shock heating. Neutron yield is shown to occur at the current minimum. The neutron yield is a result of the initial shock reflecting off the axis of symmetry, reflecting off the magnetic piston driving the focus, and reconverging on axis. Peak neutron production occurs when post‐shock plasma converges on axis.

ISSN:0003-6951    

DOI:10.1063/1.93149

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The angle of maximum reflectivity from a multilayer x‐ray reflector is influenced by absorption in the medium. Using multilayer theory we show how the full refractive correction compares to the usual correction that includes only the effect of dispersion. The physical significance of the two corrections is discussed. The absorption correction is computed for some multilayer systems of current interest.

ISSN:0003-6951    

DOI:10.1063/1.93150

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

By using glass substrates which approximate the thermal expansion of a deposited Si film, thermal stress cracking during laser crystallization is eliminated. Results on three types of transparent silicate glass are reported. Chemical vapor deposition is used to coat these substrates first with a buffer layer of SiO2or Si3N4and then with a Si film. When the Si films are melted with an argon ion laser beam, large crystal grains are produced. Secondary ion mass spectroscopy is used to determine the effectiveness of the buffer layer in isolating the Si from impurities in the glass.

ISSN:0003-6951    

DOI:10.1063/1.93137

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Measurements of the zero‐bias dc conductanceG0and high frequency capacitance have been made on GaAs bicrystals doped in the range of 4×1017–2×1018cm−3. The conductance displays a non‐Arrhenius temperature dependence with high temperature values of ∂(ln G0)/∂(1/kT) less than the barrier heights deduced from the capacitance. Theoretical calculations of transbarrier currents using the unified approach of Fonash show that thermally assisted tunneling currents are important.

ISSN:0003-6951    

DOI:10.1063/1.93138

出版商:AIP    

年代:1982

数据来源: AIP