摘要:

The recombination reaction NF2+F+Ne→NF3+Ne has been investigated experimentally in electron‐beam‐excited Ne/Xe/NF3mixtures. The results obtained are in excellent agreement with the theoretical predictions.

ISSN:0021-8979    

DOI:10.1063/1.328541

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

New laser structures have been fabricated which distribute the optical power generated within a wide injecting stripe among a multiplicity of lateral modes. This was done with the objective of increasing the life of such lasers at high power by reducing the optical stress on the facets. The levels of catastrophic optical breakdown have been measured and the very high levels achieved (≳300 mW for a 3‐spot device) have been taken as an indication of our success. These lasers were also very efficient and the mode pattern was stable to the point of breakdown. In contrast to these useful properties, it was found that intrinsic to these structures is a poor temperature coefficient of threshold, which would make them more useful for pulsed rather than cw operation.

ISSN:0021-8979    

DOI:10.1063/1.328542

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Thep‐GaAs/P‐Ga1−xAlxAs isotype heterojunction, that occurs in doubleheterostructure laser material, is studied experimentally and theoretically. In good quality liquid phase epitaxially grown material, carrier‐concentration profiles show the presence of hole accumulation in the small band‐gap material and hole depletion in the large band‐gap material. When either the layer thickness varies across the diode or the heteroboundaries are not abrupt, the profile across the isotype heterojunction becomes smeared. Hence, this profiling method can provide a sensitive measure of material quality. Furthermore, the analysis accounts for the possible presence of interface states, which can affect band bending at heteroboundaries. It is shown that this band bending can affect the recombination of carriers, and therefore their lifetimes and efficiency.

ISSN:0021-8979    

DOI:10.1063/1.328555

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A small laboratory scale cw HF laser has been built and its frequency stability is studied using a Fabry‐Perot interferometer. Performances of the free‐running laser, of the Lamb dip stabilized laser, and of the laser stabilized on a Fabry‐Perot resonance (side of a mode and derivative zero crossing) are reported. In this last case, stability close to 10−9has been observed.

ISSN:0021-8979    

DOI:10.1063/1.328543

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

InGaAsP/InP 1.3‐&mgr;m laser material grown by liquid‐phase epitaxy occasionally exhibits an anomalous x‐ray diffraction pattern and may also have a high threshold current density. The origin of this effect is shown to be the contamination of the normalp‐type InP cladding layer with Ga and As. A typical composition of this quaternary cladding layer is determined, and secondary‐ion mass‐spectrometry analyses are used to show the contamination is most likely caused by pullover from the previous melt.

ISSN:0021-8979    

DOI:10.1063/1.328544

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Degradation phenomena in Ga1−xAlxAs/Ga1−yAlyAs double‐heterostructure lasers with AlAs mole fractionsxof 0–0.17 in the active layer have been investigated. Degradation rate was found to markedly depend uponxand is a minimum value atx= 0.08. It is shown that the degradation in the lasers withxbelow 0.08 is primarily caused by the dark defects formation in the vicinity of the mirror surfaces, which is suppressed with increasingx. The degradation in the region ofx= 0.08–0.17 results from the facet oxidation, which is enhanced with increasingx. This degradation was found to be affected by the humidity of the operating ambient and was effectively suppressed with the Al2O3facet coatings. In particular, the long‐term degradation in the lasers withx= 0.08 was suppressed with increasing the humidity. Auger analysis revealed that the native oxide formed at the facet was only partially oxidized and the enhanced oxidation for largerxhad its origin in the initial stage of oxidation, where the faster oxidation rate of Al than that of Ga enhanced the oxidation. In addition, oxidation is diffusion controlled in the oxide after more than 102‐A˚ thick oxide is formed.

ISSN:0021-8979    

DOI:10.1063/1.328545

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Separation of N16O and N18O has been measured in a thermal diffusion column heated by resonant absorption of CO laser photons. For the most part, the behavior of the laser‐heated column can be adequately explained as a simple thermal effect, although the separation efficiency at low‐input powers is higher in the laser‐heated column than in a comparable hot‐wire experiment.

ISSN:0021-8979    

DOI:10.1063/1.328546

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A fluid analysis of the stability of obliquely propagating ion‐electrostatic waves to current flow along the magnetic field in a fully ionized, collisional plasma is presented. The stabilizing or destabilizing effects of frictional force, collisional energy transfer, electron and ion viscosity, electron and ion thermal conductivity, and thermal force are investigated. Simple analytical expressions for the growth rate arising from each dissipative mechanism are derived for ion‐cyclotron, cosine ion‐acoustic, ion‐acoustic, and cosine ion‐cyclotron waves.

ISSN:0021-8979    

DOI:10.1063/1.328547

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

Proton beams with currents ⩾50 kA at 5 MeV in a ≲160‐ns FWHM pulse have been extracted from an ion diode operated on the Aurora pulser. This current corresponds to an efficiency (proton currrent/total current) of 20%, which compares favorably with numerical simulation. The simulation indicates that the ion current is enhanced over the Child‐Langmuir value due to increased electron lifetime in the diode. The proton beam directed onto a LiCl target provides a source of 1.8×1012neutrons/sr/pulse in the forward direction from the7Li(p,n) 7Be reaction.

ISSN:0021-8979    

DOI:10.1063/1.328548

出版商:AIP    

年代:1981

数据来源: AIP

摘要:

A kinematical model for general Bragg case x‐ray diffraction in nonuniform films is presented. The model incorporates depth‐dependent strain and spherically symmetric Gaussian distribution of randomly displaced atoms. The model is applicable to ion‐implanted, diffused, and other single crystals. Layer thickness is arbitrary, provided maximum reflecting power is less than ∼6%. Strain and random displacement (damage) distributions in He+‐implanted Gd, Tm, Ga:YIG, and Ne+‐implanted Gd3Ga5O12are obtained by fitting the model to experimental rocking curves. In the former crystal the layer thickness was 0.89 &mgr;m with strain varying between 0.09 and 0.91%. In the latter crystal a wide range of strain and damage was obtained using successively higher doses. In each case layer thickness was 1900 A˚, with 2.49% strain corresponding to 0.40‐A˚ standard deviation of random displacements. The strain distributions were strictly linear with dose. The same, closely linear relationship between damage and implantation‐induced strain was determined for both crystals.

ISSN:0021-8979    

DOI:10.1063/1.328549

出版商:AIP    

年代:1981

数据来源: AIP