摘要:

An experiment was performed to measure the total impulse transferred to a surface by a high‐power pulsed 10.6‐&mgr; laser under atmospheric conditions, and also to determine the degree to which the observed plasma decouples the laser energy from the surface. Specific interest was directed toward conditions under which a ``radiation‐driven detonation wave'' may form due to the presence of a surface. The momentum transferred in dyn sec/J decreases with an increase in the ratio of incident energy to spot area since a larger fraction of the energy is decoupled from the surface.

ISSN:0003-6951    

DOI:10.1063/1.1654297

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

The rate of transfer of a vibrational quantum from N2to CO has been measured at room temperature using a laser‐excited vibrational fluorescence technique.

ISSN:0003-6951    

DOI:10.1063/1.1654298

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A new electro‐optic light valve, based on the Pockels effect in a KD2PO4crystal addressed by photoconduction, is described. At the present stage, the picture exhibits a resolution of 20 lp/mm (line pairs/mm), a very uniform contrast of 40/1, and an extensive grey scale; the writing time is less than 10 &mgr;sec. The device allows image addition and image subtraction and can be used as an input device in optical coherent processors.

ISSN:0003-6951    

DOI:10.1063/1.1654299

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Simultaneous Rayleigh and shear wave generation has been achieved using interdigital transducers on ayzLiNbO3sample at a frequency of 104 MHz. A large‐diameter laser beam of 5145‐Å wavelength and 1‐W cw power was transmitted through the sample and was modulated by two acoustic waves. The double‐modulated laser beam causes fringes at the recording plane, which were used for an accurate determination of the shear wave velocityvsand of the shear wave acoustic radiation angle &agr; into the crystal. It was found thatvs= 3.547 ×103m/sec for &agr; = 14.3°. The shear wave conversion loss of the transducer was approximately 6 dB.

ISSN:0003-6951    

DOI:10.1063/1.1654300

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

We have produced optical waveguides inn‐type GaAs by implantation with 300‐keV protons. The guiding is shown to be due to the elimination of charge carriers from the implanted region. Annealing of the waveguide leads to very large reductions in the 1.15‐&mgr; guided‐wave absorption.

ISSN:0003-6951    

DOI:10.1063/1.1654301

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A synthetic compound SrTeO3was discovered to exhibit ferroelectricity in the temperature range between 312 and 485°C. Small single crystals could be grown by the Kyropoulos method. The crystal belongs to the monoclinic system and its space group isC2/ c − C2 h6at room temperature. A pronounced dielectric anomaly was observed along thebaxis at 485°C. The value of the spontaneous polarization, obtained by theD‐Ehysteresis loops at 50 Hz, is 3.7 &mgr;C/cm2at 312°C.

ISSN:0003-6951    

DOI:10.1063/1.1654302

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

We report detailed measurements of current (I) vs voltage (V) on double heterojunctions (AlxGa1−xAs&sngbnd;GaAs&sngbnd;AlyGa1−yAs) at very high injection levels which reveal nearly discontinuous ∂2V/∂I2at currents ∼ 30% below lasing threshold. This behavior persists unchanged after the laser mirrors are destroyed. A similar breakpoint in ∂2V/∂I2is found on nonlasing double heterostructures and correlates with the onset of intense infrared emission.

ISSN:0003-6951    

DOI:10.1063/1.1654303

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

The cross sections of both amplitude and phase holograms are observed by electron microscopy. Holograms were recorded on Kodak 649F and Scientia 14C75 sheet films by using a He&sngbnd;Ne laser beam (6328 Å). It is shown that the holograms are recorded throughout the whole thickness of the emulsion layer and the developed grains are enlarged by bleaching (about 1.5 times by length). This enlargement can be correlated with the thickness change of the emulsion layer during the chemical processing in making holograms.

ISSN:0003-6951    

DOI:10.1063/1.1654304

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Optical surface waveguides have been fabricated by diffusing selenium into single‐crystal CdS substrates to produce graded‐composition CdSxSe1−xcrystals. Planar guides which confine a beam in one dimension and guides produced by masked diffusion capable of two‐dimensional beam confinement have been obtained. Evidence of guiding of light from a HeNe laser is provided by photographs and by measurements of spatial intensity profiles. Losses are estimated to be 10–15 dB/cm for one‐dimensional guides and 30–40 dB/cm for two‐dimensional guides.

ISSN:0003-6951    

DOI:10.1063/1.1654305

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

The spontaneous emission behavior of a cw stripe‐geometry GaAs laser is examined in detail. Contrary to recently published results, a sharp discontinuity of the spontaneous emission growth occurs when the laser reaches threshold. Above threshold, slow increases in the spontaneous emission are observed, coming mostly from the regions where the lasing light intensity is small. Other discontinuity points were, at higher currents, observed corresponding to the onset of higher‐order modes and second‐order mode locking.

ISSN:0003-6951    

DOI:10.1063/1.1654306

出版商:AIP    

年代:1972

数据来源: AIP