摘要:

A new type of guided ultrasonic wave bound to a fluid layer between two elastic solids has been observed. Quantitative agreement has been obtained between experiment and theory.

ISSN:0003-6951    

DOI:10.1063/1.1653199

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The presence of a liquid layer on the Rayleigh wave delay line is found to increase the original delay by a factor of 2 with loss of only a few percent in amplitude. Different modes with variable delay can be excited simultaneously and can be picked up by another transducer in contact with liquid layer. Possible uses of thin layer waves as an acoustic interferometer are discussed.

ISSN:0003-6951    

DOI:10.1063/1.1653200

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

We report on the observation of backward wave acoustic oscillations in LiNbO3. We have confined our study to fast shear waves propagating along thexaxis, and we have been successful in generating these waves at a frequency of 1.43 GHz with a spatially uniform electric field at 2.86 GHz applied along thezaxis. In addition, it has been possible to observe 60 dB of gain for an injected acoustic signal. Maximum peak strains are estimated to be in excess of 5 × 10−4.

ISSN:0003-6951    

DOI:10.1063/1.1653201

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The nonlinear coefficients of lithium iodate have been measured, relative to quartz, by the Maker fringe technique.d31(LiIO3) = 15.5 ± 0.8 d11(SiO2),  d33(LiIO3) = 16.1 ± 1 [d11(SiO2)]for the fundamental wavelength 1.064&mgr;. It has also been determined thatd31andd33have the same sign.

ISSN:0003-6951    

DOI:10.1063/1.1653202

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

We show that acoustic surface waves on a piezoelectric can be resonantly amplified by coupling to a weakly damped carrier surface wave on an adjacent semiconductor in which the conduction electrons are made to drift across an applied magnetic field. The conditions for such a wave‐wave interaction are established, and calculations of the growth rate and its characteristics are given. Under the same conditions, reversing the direction of the magnetic field changes the amplifier to an almost loss‐free, tunable, coupler.

ISSN:0003-6951    

DOI:10.1063/1.1653203

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Quasi‐cw stimulated Raman emission in the visible has been obtained from an oscillator cavity with a pump‐power input of less than 5W. This large reduction of oscillator threshold is achieved with the use of a liquid‐core optical waveguide structure. Significant conversion of pump to Stokes light has been observed. Extension of the system to continuous operation and to the study of other nonlinear effects is suggested.

ISSN:0003-6951    

DOI:10.1063/1.1653204

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The spin‐wave spectrum of a long axially magnetized strip of noncircular cross sections is examined. The results are related to the limiting cases of the (1) ferromagnetic slab and (2) the circular cylinder. It is found that the elliptical cylinder results can be identified with the infinite‐film results of Damon and Eshbach whenk, the propagation constant along the long axis of the ellipse, is identically equal to zero. This identification leads to a geometrical quantization of the wave vector in the infinite‐film calculation. Fork≠ 0 no simple quantization scheme can be used to relate the elliptical cylinder results to the infinite film results.

ISSN:0003-6951    

DOI:10.1063/1.1653205

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Efficient internal optical parametric oscillation has been obtained using a LiNbO3crystal inside the resonator of a continuously pumped repetitively Q‐switched 1.06&mgr; Nd:YAG laser. Dielectric mirrors are coated directly on the plane‐parallel end faces of the crystal, and no focusing optics are used inside the laser. The oscillator operates near degenerate with outputs near 2&mgr;. Average output powers as high as 350 mW and 75 % depletion of the available pump power are observed. This represents an order of magnitude larger output power than previously reported for a parametric oscillator. Internal oscillation causes stretching of the laser pulses to as much as five times the normal length, with corresponding increases in oscillator pulse length. Operation of this internal oscillator is compared to that of a similar external oscillator pumped by the same laser.

ISSN:0003-6951    

DOI:10.1063/1.1653206

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

An energy product of 12.3 × 106G‐Oe has been obtained on cast samples of a cobalt rare‐earth permanent magnet having the composition Co3.3Fe0.5Cu1.2Ce0.25Sm0.75. This exceeds the former high value of 9.8 × 106G‐Oe obtained in an alloy of Co3.8Fe0.5Cu0.9Ce.

ISSN:0003-6951    

DOI:10.1063/1.1653207

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Channeling‐effect measurements have been used to investigate the lattice location of boron atoms implanted into silicon at an energy of 56 keV and with doses in the interval 1014–1015ions/cm2. Measurements have been made as a function of implantation temperature and subsequent anneal treatment. The effect of post‐bombardment with different doses of 680‐keV protons has also been investigated.

ISSN:0003-6951    

DOI:10.1063/1.1653208

出版商:AIP    

年代:1970

数据来源: AIP