摘要:

We extend the stability analysis of the quasioptical equation given by Bespalov and Talanov and by Suydam to the case of Frantz‐Nodvik pulse propagation. When&egr; ≈ (An0g0/2 &pgr; &lgr;)2≪ 1, we find that the logarithm of the perturbation growth divided by the input intensity depends on the input illuminance and the media gain. This relationship is important in amplifier design. The asymptotic growth may be given in closed form even when&egr; ≫ 1. This form is used for design refinements when indicated by ana posterioriestimate.

ISSN:0003-6951    

DOI:10.1063/1.1655107

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A deuterium‐filled &thgr; pinch was axially irradiated in the first half‐cycle by a CO2laser to demonstrate the effects of beam trapping and absorption by a plasma. Peak electron densities were 5×1016cm−3and the nonirradiated axial temperature was about 1.3 eV. Detection of the laser radiation transmitted through the plasma showed that beam trapping occurred when the density profile had a minimum on axis, and the maximum laser‐induced temperature increase of 2 eV occurred for irradiation at the time of maximum density, in agreement with inverse bremsstrahlung predictions. Furthermore, the plasma emission histories indicated that the column underwent a laser‐induced elongation of up to twice its original length.

ISSN:0003-6951    

DOI:10.1063/1.1655108

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

An application of a dye solution for wavefront multiplication is described. In this application, two coherent pumping laser beams generate a spatial gain and index‐of‐refraction distribution in a dye amplifier. This distribution is used to modulate the amplitude and phase of an optical field in the amplification band of the dye in order to form a new wavefront. To establish that the multiplication is due to singlet‐state effects and not to triplet‐state excitation, the lifetime of the information in the dye cell is measured.

ISSN:0003-6951    

DOI:10.1063/1.1655109

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Scanning electron microscope (SEM) observation of magnetic domains in a polycrystalline pure nickel sheet was made possible through the use of a 50‐kV accelerating potential. The contrast was unobservable in an SEM capable of only a 30‐kV accelerating potential.

ISSN:0003-6951    

DOI:10.1063/1.1655110

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

We have subjected sputtered amorphous films of Gd&sngbnd;Co alloys to a high‐energy argon ion flux to study the effects of ion radiation damage on the uniaxial anisotropy of these materials. We find that a relatively low level of radiation damage ([inverted lazy s] 1014ions/cm2) can destroy the uniaxial anisotropy if the damage is sustained in zero applied fields. A similar dosage can induce anisotropy if a strong magnetic field is applied during the ion irradiation. These experiments support the atomic‐pair‐ordering model of anisotropy in these materials.

ISSN:0003-6951    

DOI:10.1063/1.1655111

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The measured performance of Nb&sngbnd;Nb point contact Josephson junctions used as 36‐GHz microwave mixers is in good agreement with the predictions of the resistively shunted junction model. Conversion efficiencies greater than unity are attained, with mixer noise temperatures comparable with the best competing devices.

ISSN:0003-6951    

DOI:10.1063/1.1655086

出版商:AIP    

年代:1974

数据来源: AIP