摘要:

This paper describes a theoretical study of the diffraction of Bleustein‐Gulyaev waves at surface imperfections. With the use of the integral representations of the shear‐horizontal waves in a semi‐infinite piezoelectric material, simultaneous integral equations are obtained. Moment methods are applied in order to solve these equations. To obtain a qualitative idea of the propagation characteristic of Bleustein‐Gulyaev waves at surface imperfections, numerical illustrations of the power transmission coefficient, power reflection coefficient, and the scattering power coefficient are shown.

ISSN:0003-6951    

DOI:10.1063/1.89944

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A real‐time correlator has been developed that utilizes successive acousto‐optic interactions in two adjacent piezoelectric crystals (lithium niobate, LiNbO3, and bismuth germanium oxide, BGO) having surface‐acoustic‐wave (SAW) propagation velocities that differ by almost a factor of 2. Complex waveforms, such as FM chirps and Barker codes, have been correlated successfully. A large time‐bandwidth product (∼3000) was obtained, and a 40‐dB dynamic range was shown to be feasible. The use of this two‐crystal device to obtain either pulse expansion or time inversion of a signal also was demonstrated.

ISSN:0003-6951    

DOI:10.1063/1.89945

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Radiation at &lgr;∼1 cm and megawatt power level is observed when a rotating, relativistic electron beam interacts with a background plasma. The emission spectrum is peaked at the 20th cyclotron harmonic, and the parametric dependence of the radiation is consistent with a model of interaction between single‐particle cyclotron radiation and a beam‐plasma streaming instability.

ISSN:0003-6951    

DOI:10.1063/1.89946

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Propagating ir surface electromagnetic waves have been launched on and off the edges of a metallic film evaporated on the base of an NaCl prism. The coupler does not make use of an air gap or a grating.

ISSN:0003-6951    

DOI:10.1063/1.89947

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The surface scattering of MeV He+ions channeled along Si⟨100⟩ from clean well‐characterized Si(100) surfaces is measured. The surface peak intensity, along with other values in the literature, is shown to obey simple scaling laws. For the study of very thin films by backscattering the contribution made by this surface scattering can be important.

ISSN:0003-6951    

DOI:10.1063/1.89948

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The optical attenuation induced in polymer‐clad silica fiber‐optic waveguides by low‐dose ionizing radiation (0.5–14 MeV) has been found to be much greater than expected on the basis of previous high‐dose measurements. The radiation sensitivity is dependent upon the purity and OH content of the silica and upon the radiation history of the fibers, but it does not appear to depend upon the drawing conditions nor on the limited radiation‐induced loss in the polymer cladding. The damage is greater at short times following the irradiation, and the decay kinetics of different synthetic silica fibers are qualitatively the same.

ISSN:0003-6951    

DOI:10.1063/1.89949

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The absorption coefficients of four commercial silicas (Spectrosil WF, Spectrosil A, Suprasil W2, Suprasil 2) have been measured over the energy range 6.2–8.1 eV. The absorption in the neighborhood of the edge varies markedly with water content. A peak or a shoulder is observed at 7.6 eV (an energy below the absorption edge) in the water‐free samples. In samples containing significant OH, no structure at energies lower than the fundamental edge is observed. The absorption edge for the dry silica occurs at an energy 0.2 eV higher than for the wet silica.

ISSN:0003-6951    

DOI:10.1063/1.89950

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The first demonstration of cw parametric upconversion inside a laser’s optical cavity is reported. Infrared radiation &lgr;=3.39 &mgr;m was upconverted using a 5145‐A˚ argon laser pump and a lithium niobate crystal.

ISSN:0003-6951    

DOI:10.1063/1.89951

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Tunable subpicosecond pulses (pulse width =0.8 psec) have been obtained from a cw mode‐locked Rhodamine B dye laser. Mode locking is achieved by synchronous pumping of the Rh‐B dye with a cw train of pulses which are obtained from a synchronously mode‐locked Rhodamine 6G dye laser.

ISSN:0003-6951    

DOI:10.1063/1.89952

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A generalized analysis of wave propagation in periodic layered media is applied to the special case of optical surface waves. These waves, confined to the interface between a periodic layered medium and a homogeneous medium, are formally analogous to electronic surface states in crystals. Single‐mode surface‐wave propagation along the surface of a GaAs‐AlGaAs multilayer stack (grown by molecular‐beam epitaxy) has been observed experimentally.

ISSN:0003-6951    

DOI:10.1063/1.89953

出版商:AIP    

年代:1978

数据来源: AIP