摘要:

Elastic surface waves have been generated and propagated in thin ZnS films on single crystals of Al2O3. Measurements of surface waves on these films have revealed a dispersive behavior in the velocity of propagation. At frequencies when the film thickness is greater than the wavelength, the surface wave velocity approaches 95% of the bulk shear velocity in ZnS. At lower frequencies, the velocity increases towards the bulk shear velocity in the Al2O3substrate material.

ISSN:0003-6951    

DOI:10.1063/1.1653214

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Several superconducting TM010mode Nb cavities at 8.6 GHz with high measured unloadedQ's and fields were made using commercial reactor‐grade Nb, practical fabrication techniques, and practical processing techniques. The cavities were fabricated by machining the cavities in two parts from a solid billet of Nb and then joining the two parts with electron‐beam welding. The cavities were processed primarily by using ultra‐high‐vacuum firing (1750–2100 °C) and chemical polishing. UnloadedQ's as high as 1011were measured at low field levels, and surface fields as high as 1080 Oe and 70 MV/m were obtained with unloadedQ's on the order of 1010.

ISSN:0003-6951    

DOI:10.1063/1.1653215

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

We have fabricatedn‐pjunction photovoltaic detectors in InSb using proton bombardment to create then‐type layer. At 77 °K, diodes which were 20 mils in diameter had zero‐bias resistances of several hundred thousand ohms. The peak detectivity at 4.9 &mgr; of these diodes with a 2&pgr;, 300 °K background was typically greater than 3×1010cm Hz1/2/W with the largest value observed being 1011cm Hz1/2/W. Diode quantum efficiencies near 35% were observed.

ISSN:0003-6951    

DOI:10.1063/1.1653216

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A repetitivelyQ‐switched Nd: YAG laser has been operated with an intracavity second harmonic generator to produce 1‐W average power at 0.53 &mgr;. The output coupling optimization of this system has been determined from a simplified model and the results of a computer solution are presented, and compared with the optimization condition for the cw mode of operation. Finally, the dependence of the average output power for theQ‐switched mode of operation on the pulse rate is calculated and compared with experimental data.

ISSN:0003-6951    

DOI:10.1063/1.1653217

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A red‐orange photoluminescence emission band which peaks at approximately 2.02 eV was found in TiO2: W. The excitation and emission spectra for this band are presented. The previously reported 1.46‐eV photoluminescence emission band which was attributed to interstitial Ti3+ions is found to be quenched in the presence of tungsten. This result is interpreted in terms of the reduction of interstitial Ti3+ions in the presence of tungsten. The 2.02‐eV band is tentatively identified as an electron transition from states at or just below the conduction‐band edge to an acceptorlike level approximately 1 eV above the edge of the valence band.

ISSN:0003-6951    

DOI:10.1063/1.1653218

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

In a Gunn effect oscillator operating in the transit‐time mode, domains of high electric field are formed periodically and travel through the device. When such an oscillator is placed close to the surface of a piezoelectric solid the moving high‐field domains produce moving local stress concentrations in the piezoelectric, causing the radiation of elastic waves into the body of the piezoelectric and along its surface. The domain velocity is much higher than the elastic wave velocities, so the situation is similar to that of Cherenkov radiation, and the waves are emitted at a large angle to the direction of domain motion. Results are given on the generation of bulk and surface waves at a fundamental frequency of 114 MHz in a lithium niobate crystal coupled to a gallium arsenide Gunn effect oscillator.

ISSN:0003-6951    

DOI:10.1063/1.1653219

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A gatedp‐njunction diode has been used to study the effects of neutron damage on the various lifetime parameters in silicon. Isochronal annealing of heavily irradiated devices leads to the observation of two annealing stages: one in the 150–250°C range corresponding to the previously reported divacancy anneal, and the other in the 300–400°C range corresponding to the anneal of oxygen associated defects. The diffusion current, the space‐charge generation current, and the space‐charge recombination current show similar annealing behavior, suggesting that the damage complexes in the space‐charge region are essentially of the same nature as those in the neutral bulk region.

ISSN:0003-6951    

DOI:10.1063/1.1653220

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A new type of retarding potential difference electron spectrometer using spherical grids is described. The unique feature of the analyzer is a post monochromator section which selectively collects electrons passing the retarding grids with minimum kinetic energy. Factors affecting the resolution of the analyzer are discussed and a comparison with several other spectrometers operating in the resolution range of 0.05% is presented. An application to x‐ray photoelectron spectroscopy is presented.

ISSN:0003-6951    

DOI:10.1063/1.1653221

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A current‐tunable Pb0.88Sn0.12Te diode laser was used to obtain the absorption spectrum of SF6near theP(16) andP(20) CO2laser lines at 10.6&mgr;m by both direct and heterodyne techniques. Because of its narrow linewidth, the diode laser can perform high‐resolution spectroscopy beyond the limits of conventional instruments moreover, its infrared frequency can be tuned continuously over a range much greater than attainable with a gas laser.

ISSN:0003-6951    

DOI:10.1063/1.1653222

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The wavelength of laser emission from an electron‐beam‐pumped ZnO was measured in the temperature range from 82 to 250°K. The laser emission occurred near the line due to the annihilation of a free exciton assisted by one LO phonon at 82°K. Above 180°K the laser emission occurred near the line due to the transition assisted by two LO phonons. From 130 to 170°K the laser oscillation appeared in two spectral lines. The temperature dependence of threshold current density measured from 82 to 250°K was weak compared with the theoretical curve based on the laser action involving the A‐LO line.

ISSN:0003-6951    

DOI:10.1063/1.1653223

出版商:AIP    

年代:1970

数据来源: AIP