摘要:

Artificial depolarization and anisotropy induced broadening of the Raman spectra recorded in air from small RbClO3single crystals of extremely poor optical quality can be effectively eliminated by immersion of the sample in an index‐matching fluid. Measurement temperatures as low as − 110°C have been obtained using a commercial cryostat fitted with a specially designed sample support system.

ISSN:0003-6951    

DOI:10.1063/1.1654100

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Room‐temperature cw laser operation well into the visible spectrum (&lgr; ∼ 6000 Å) is reported for In1−xGaxP (x≤ 0.60). Thin (1–5‐&mgr;) experimental samples are compressed into In, under a thick (∼ 250‐&mgr;) high‐index (&eegr; > 2. 6) SiC window, with a thin (10–50‐&mgr;) narrow SiC platelet under part of the In1−xGaxP sample. The thin In1−xGaxP samples, in the compound cavity, are volume excited in a small spot with an argon laser so that the heat is easily removed by the SiC windows and nearby In heat sink.

ISSN:0003-6951    

DOI:10.1063/1.1654101

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Measurements of transient conductance in response to 80‐nsec pulses of 4–20‐keV electron irradiation have been used to investigate electrical properties of defects in 2–4‐&mgr; Si films on ⟨111⟩ MgO·Al2O3spinel. Carrier lifetimes ∼ (2–3) × 10−10sec are estimated from the conductance change during irradiation. Significant trapping of injected carriers is indicated by the postirradiation conductance decay, which persists beyond 10−5sec at 300°K and 10−3sec at 90°K. The time and temperature characteristics of the decay suggest that ionized defects equilibrate by carrier capture over a potential barrier as in neutron‐irradiated silicon. Variable‐energy electron irradiation was used to investigate the depth dependence of defect density, and the results indicate that trapping in Si/spinel is greater near the substrate inferface.

ISSN:0003-6951    

DOI:10.1063/1.1654102

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

The structure of moving domain walls in thin films having a uniaxial anisotropy axis in the plane of the film is calculated by a variational method. The calculation applies for wall velocities &ngr; smaller than a critical velocity at which the derivative of the wall energy with respect to &ngr; becomes infinite. At intermediate film thicknesses the critical velocity is much smaller, the effective wall mass (per unit area) much larger than for bulk crystals and/or very thin films.

ISSN:0003-6951    

DOI:10.1063/1.1654103

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

High‐frequency small‐signal capacitances of semiconductor junction vs temperature, from the initial conditions of filled and emptied traps in the junction depletion region, are used to determine the trap concentration and the thermal activation energies of trapped electrons and holes. Illustrations are given for siliconN+Pdiodes doped with gold impurity or irradiated with 1‐MeV electrons, showing the room‐temperature annealing for the latter.

ISSN:0003-6951    

DOI:10.1063/1.1654104

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Stimulated emission near 3371 Å is reported for the first time using a commercial electron‐beam generator as an energy source. A 2 × 103‐A/cm23‐nsec pulse of 400‐keV electrons from a field‐emission diode traveled 160 cm down a ¾‐in. tube containing N2at pressures of 10–50 Torr. A longitudinal magnetic field of 2–10 kG helped confine the electrons in the tube. The 400‐keV electrons produce secondary and subsequent cascade electrons with energies from 0–200 keV. Those electrons with 13–17 eV excite nitrogen molecules to the upper lasing (C3&Pgr;u) state. Sufficient concentration of excited nitrogen molecules is produced for the gas to show superradiance with 60 kW of light output power.

ISSN:0003-6951    

DOI:10.1063/1.1654105

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

LiNbO3has been found to emit strong luminescence when irradiated by a ruby laser beam. The luminescence varies linearly with input power, is broad band, independent of crystal orientation, and decreases exponentially with the inverse absolute temperature, as does the luminescence decay time. The effect is closely related to so‐called ``optical index damage'', and provides a new means for studying that phenomenon.

ISSN:0003-6951    

DOI:10.1063/1.1654106

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Spatially uniform birefringences tunable over the range 0. 0–0. 15 for applied voltages less than 20 V rms and with a sharp threshold below 4 V rms are obtained for thin layers of nematic liquid crystals with negative dielectric anisotropy. The achievement of spatially uniform tunable birefringence with negative‐dielectric‐anisotropy materials requires a source of in‐plane anisotropy which is provided by a unique previously unreported molecular configuration at zero field. AtV=0, the molecules align with their long axes at a small angle to the sample normal. The experimental results are analyzed in terms of a continuum model and experimental values obtained for the relevant elastic constants.

ISSN:0003-6951    

DOI:10.1063/1.1654107

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

We report herein the preparation of a form of noncrystalline Ge film by rf sputtering on to various substrates, which crystallizes with ``explosive'' velocities when triggered by a localized transient energy pulse. The films show this phenomenon only when they are thicker than about 10 &mgr;. The crystallization wave appears to be acoustically transmitted.

ISSN:0003-6951    

DOI:10.1063/1.1654108

出版商:AIP    

年代:1972

数据来源: AIP

ISSN:0003-6951    

DOI:10.1063/1.1654111

出版商:AIP    

年代:1972

数据来源: AIP