摘要:

Calculations of the electron energy distribution function in mixtures of Se(1S), CO, and Xe are presented. The Se(1S) arises from photolysis of OCSe by Xe2vacuum ultraviolet excimer radiation, and the electrons are due to photoionization of the Se(1S). The calculations show that highly non‐Maxwellian electron energy distribution can result from electron heating by super‐elastic deexcitation of Se(1S) and cooling by inelastic excitation of CO vibrational levels and Xe electronic states. The kinetic rate constants computed using these distributions differ significantly from those derived from a Maxwellian distribution. It is found that the kinetic rate constants are sensitive to variations in the fractional ionization (&agr;≳10−6), relative CO concentration (nco/nSe(1S)⩾1), CO vibrational temperature (Tv≳1000 °K), and fractional Xe metastable density (n*/n≳ 10−5). Adding the molecular buffer, CO, cools electrons and slows multiplication.

ISSN:0003-6951    

DOI:10.1063/1.92122

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Spatially uniform avalanche discharges of relatively long duration have been obtained in a UV‐preionized, high‐pressure, rare‐gas–halide laser. In the case of XeCl pulse durations as long as 70 ns have been observed. The spatial distribution of the small‐signal gain in a plane transverse to the laser axis has been measured. The active discharge cross sections with better than 90% gain uniformity were 2.8×3.0 and 2.8×2.5 cm2for XeCl and KrF, respectively. The use of neon rather than helium as a buffer gas increased the discharge cross section, and the laser pulse duration resulting in improved laser output energy densities of 4.5 J/l in XeCl and 2.8 J/l in KrF.

ISSN:0003-6951    

DOI:10.1063/1.92125

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

We present the results of the cw electro‐optical characteristics of 5‐&mgr;m shallow proton‐bombarded strip laser fabricated from molecular beam epitaxy (MBE)‐grown double‐heterostructure (DH) wafers that have Al0.08Ga0.92As active layers at elevated temperatures (55–70 °C), and compare them with those obtained from similar lasers fabricated from liquid phase expitaxy (LPE)‐grown DH wafers. It is shown that the MBE lasers maintain their excellent cw device characteristics even at elevated temperatures. The temperature dependence of the cwIthof MBE lasers is significantly less than that of the LPE lasers. Furthermore, the cwIth’s of these MBE lasers are at least as good as good LPE lasers. Owing to the very uniform layer thicknesses generated by the MBE process, the resultant slice quality is highly uniform. This results in a significantly increased yield of good lasers per MBE wafer.

ISSN:0003-6951    

DOI:10.1063/1.92133

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Delayed laser emission from a ND‐YAG oscillator pumped by a 532‐nm 50‐ns pulse is interpreted in terms of multiphonon relaxation from the pumped levels to the upper laser level. The relaxation rate constant, (1.6±0.2)×106s−1, is in good agreement with previous results obtained from the fluorescence rise time.

ISSN:0003-6951    

DOI:10.1063/1.92134

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The aim of this letter is to give a short description of some electro‐optical effects which are observed in aDFphase of disklike molecules. We point out the existence of dielectric and electrohydrodynamic instabilities. The last one is the experimental evidence of the interesting situation of an anisotropic liquid with &egr;a≳0&sgr;a<0 in the homeotropic configuration. These electro‐optic effects can be useful in display applications of the discotic phases.

ISSN:0003-6951    

DOI:10.1063/1.92118

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Raman‐spectra measurements were made on semi‐insulating (SI) GaAs heat‐treated in an atmosphere of H2or Ar to study the effect of structural changes or strains on a thermal conversion of Si GaAs. Correlations between Raman spectra and electrical changes of SI GaAs indicate that strains in the interface region between SI GaAs and a dielectric film is, at least, one of the origins of the thermal conversion, while the structural changes accompanying the generation of the TO‐phonon line has no effect on the thermal conversion.

ISSN:0003-6951    

DOI:10.1063/1.92119

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Aging tests of InGaAsP/InP double‐heterostructure (DH) laser diodes with single transverse mode have been performed at 50 and 70 °C under constant optical power operation. The devices were self‐aligned‐structure DH laser diodes bonded with AuSn‐alloy solder. Samples for 3‐mW/facet operation at 50 °C are operating at over 5000 H, those for 5‐mW/facet operation at 50 °C are operating at over 4500 H, and those for 3‐mW/facet operation at 70 °C are operating at over 3500 H. Far‐field patterns parallel to the junction plane in these samples do not change in this aging. Averaged increasing rates of the driving current to maintain the specified optical power are 1.8×10−6/H for 3‐mW operation at 50 °C, 48×10−6/H for 5‐mW operation at 50 °C, and 1.3×10−5/H for 3‐mW operation at 70 °C.

ISSN:0003-6951    

DOI:10.1063/1.92120

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The first use of a variational approach to analyze the growth of a localized filament on an optical plane wave in a nonlinear medium shows that saturation of the nonlinearity of the medium by the wave can suppress filamentation of the wave. Applications may include lossless filters that remove hot spots from beams or convert multimode beams to single mode.

ISSN:0003-6951    

DOI:10.1063/1.92121

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

The effects of Pierce‐type space‐charge instabilities in high‐energy ion beams, initially neutralized by co‐moving electrons, are discussed in terms of planar and two‐dimensional spherical geometries. The limiting ion current which can reach a target is given.

ISSN:0003-6951    

DOI:10.1063/1.92123

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Helium particles backscattered from the surface of a Nb plate bombarded with 40‐keV He+were used as incident particles for studying the effect of the distribution of incident energies on blistering. After the bombardment, blisters with irregular shapes and sizes were observed on the surface of polycrystalline Mo.

ISSN:0003-6951    

DOI:10.1063/1.92112

出版商:AIP    

年代:1981

数据来源: AIP