摘要:

A surface acoustic wave planar resonator is described in theory and experiment. The resonance is due to energy storage within an interdigital transducer. Experimental results are reported for a one hundred finger pair double electrode transducer onYZLiNbO3which exhibited a resonanceQof 1900 at 34 MHz. The resonator is unique in that the resonant frequency is not determined by material dimensions and many such devices can be fabricated upon a common substrate.

ISSN:0003-6951    

DOI:10.1063/1.1655509

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Misfit dislocations in epitaxially grown layers of GaAs1−xPxwith a lattice constant gradient were examined by weak beam TEM. They are dissociated into partial dislocations and in specimens with (113) growth planes they form networks of extended and contracted nodes on (111) planes. The dissociation corresponds to an intrinsic stacking fault energy of 43 erg/cm2for GaAs0.7P0.3.

ISSN:0003-6951    

DOI:10.1063/1.1655510

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A new type of topographic acoustic surface waveguide which uses substrate anisotropy is described. In this guide the velocity reduction at the center of a hump or depression on the substrate is primarily due to the change in crystal cut rather than a reduction in material constraint as in other topographic guides. Experimental results obtained on the (001) apex of a 110 axis Bi12GeO20rod are in good agreement with the predictions of a ``lenslike media'' theory based on parabolically approximated wave surfaces.

ISSN:0003-6951    

DOI:10.1063/1.1655511

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A new type of noncollinear acousto‐optic filter with large angular aperture is described. By an appropriate choice of acoustic wave propagation direction, the momentum mismatch caused by the angular deviation of the incident light from the matching condition in a noncollinear interaction can be compensated by the angular change of optical birefringence. A TeO2noncollinear acousto‐optic filter was constructed that had a half‐power bandwidth of 40 Å at anf/4 (±7°) aperture. Tuning from 700 to 450 nm is obtained by changing the acoustic frequency from about 100 to 180 MHz. About 95% maximum transmission is obtained with an electrical power density of 1 W/cm2applied to the transducer.

ISSN:0003-6951    

DOI:10.1063/1.1655512

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The interaction of light with the field of the alternating strains produced by inhomogeneous acoustic surface waves may enable one to guide light beams underneath the surface of solid media. The evaluation is made of the convergence which may be attained for light beams which collinearly propagate with the acoustic waves. Maximum spreading angles are obtained which are equal to a fractional variation of the refractive index induced by the stress wave of the order of 0.1 &Dgr;n/n.

ISSN:0003-6951    

DOI:10.1063/1.1655513

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The electronic nonlinear refractive index in Cs vapor at 1.06 &mgr; is shown to be negative and to consist of two distinct contributions. One of these contributions arises from a two‐photon resonance in the susceptibility and can be made comparable in magnitude to the positiven2in laser glass. The other term arises from population redistributions between the ground and first excited state. We present measurements of self‐defocusing of a single pulse from a Nd: YAG mode‐locked laser that are in agreement with the theoretical predictions.

ISSN:0003-6951    

DOI:10.1063/1.1655514

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Interaction of a high‐frequency electromagnetic pump wave with a magnetized plasma is analyzed. Enhanced growth rates for parametric instability are found near cyclotron resonance. The result implies that tunable high‐power submillimeter sources could be developed using intense relativistic electron beams.

ISSN:0003-6951    

DOI:10.1063/1.1655515

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A 2‐MeV 15‐kA 45‐nsec electron beam was used to obtain high‐energy deuterons when injected into a chamber filled with neutral deuterium at low pressure. It was found that ion acceleration did not occur until the electron current exceeded the space‐charge limiting current, the threshold established by the acceleration model of Olson. The limiting current was varied through its dependence on the ratio of guide tube radius to injected electron beam radius. The maximum deuteron energy was measured to be 4.5 MeV for the largest guide tube to beam radius ratio. An increasing average ion energy with an increasing radius ratio was also observed.

ISSN:0003-6951    

DOI:10.1063/1.1655516

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

We have improved the resolution of neutron diffraction topography by working with a low‐divergence primary beam from a neutron guide tube and using an almost perfect monochromator. As a result, we have obtained neutron topographs revealing, although with a resolution still very inferior to that of x‐ray topography, subgrain boundaries and inclusions in a Fe‐2.5 wt% Si single crystal, as well as some individual dislocations in a germanium single crystal. Their contrast is compared with that of x‐ray topographs of the same specimens and discussed.

ISSN:0003-6951    

DOI:10.1063/1.1655517

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The first experimental verification of phase‐matched SHG was performed in the polycrystalline ZnS thin‐film waveguide deposited on a BK‐7 glass substrate. The complete phase‐matching between the TE1mode at the fundamental frequency of 1.054 &mgr;m and the TM4mode at its second harmonic wave was realized by using a tunable optical parametric oscillator. The interaction length estimated from the tuning curve for the phase matching was about 35 &mgr;m and the output harmonic power was of the order of milliwatts at 300‐W fundamental input under the phase‐matched condition.

ISSN:0003-6951    

DOI:10.1063/1.1655518

出版商:AIP    

年代:1974

数据来源: AIP