摘要:

The fabrication of an extremely‐low‐loss glass optical waveguide, having as little as 4 dB/km total attenuation, has allowed interpretation of the absorption spectrum to a much greater degree than previously possible. It is shown that, beyond about 700 nm, intrinsic ultraviolet absorption will have no effect. Between 700 and 1100 nm, all absorption can be accounted for on the basis of OH to within ±0.7 dB/km. Marked reduction of the water content will leave the scattering as the major loss mechanism, thereby permitting total attenuations of about 2 dB/km.

ISSN:0003-6951    

DOI:10.1063/1.1654649

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Based on the simultaneous measurement of length and transit time of a specimen under pressure, we have developed a new way of determining absolute high pressure. The mercury freezing point at 0 °C has been determined with this new method at 7571.2±1.6 bar. Accurate high‐pressure calibration of a secondary‐pressure gauge such as a manganin gauge is possible with this method. The maximum deviation from linearity of the present gauge studied is 11.6±0.1 bar between atmospheric pressure and the mercury freezing point at 0 °C.

ISSN:0003-6951    

DOI:10.1063/1.1654650

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A special type of 180° domain wall which we call a ``compensation wall'' is observed in (111)‐oriented wafers with the chemical composition Y3Fe5−tGatO12, wheret≈1.3. The compensation wall aligns along the sites of magnetic compensation (Ms=0) normal to the lateral gradient oftand is distinguished from a regular Bloch wall by essentially three properties: (i) The location of the wall remains unchanged under varying external magnetic fields; (ii) the wall thickness depends strongly on the applied magnetic field; and (iii) the wall moves with changing temperature.

ISSN:0003-6951    

DOI:10.1063/1.1654651

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Polymer foils carrying thin vacuum‐deposited electrodes on both surfaces are irradiated with nonpenetrating monoenergetic electron beams of various energies. Measurement of the currents and charges drawn from both electrodes and of the voltage buildup between the electrodes during and after irradiation allows one to determine charge storage parameters of such electrets.

ISSN:0003-6951    

DOI:10.1063/1.1654652

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A simple quantitative formulation of transit‐time‐limited wall motion is used to show that such an effect can reasonably explain the observed nonlinear wall motion in Permalloy thin films. The ``critical velocity'' is calculated by equating the intrinsic relaxation timeTito the transit timeTtfor the wall past an individual spin position to obtainVcrit=&dgr;/Ti, where &dgr; is the wall width. The model correctly predicts (i) the magnitude and (ii) variation with film thickness of the observed knee in the velocity‐field curves for wall motion in Permalloy films.

ISSN:0003-6951    

DOI:10.1063/1.1654653

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

A hydrogen fluoride chemical laser has been constructed with high‐voltage pulse initiation in a simple transverse discharge geometry. The system delivers a maximum pulse energy of 11 J with about 100‐nsec half‐width. This corresponds to an efficiency of nearly 4&percent; with respect to the electrical input into the pulse generator. An investigation of the voltage and the current flow across the discharge chamber, however, indicates that the efficiency with regard to the actual energy deposition in the gaseous discharge is considerably higher. The discharge parameters for optimum operation are discussed.

ISSN:0003-6951    

DOI:10.1063/1.1654654

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

V‐T rates for the CO2(1000) and (0001) levels have been measured in various 10.6‐&mgr;m amplifying and absorbing glow discharges by a simple new technique. The rise and decay times of the changes produced in the discharge current by a short‐duration 10.6‐&mgr;m laser pulse are interpreted in terms of the V‐T rates. Reciprocal rise and decay time plots vs pressure yield straight lines, the slopes of which are the average molecular V‐T rates for the (1000) and (0001) levels. Provided the electron density is known, the electron deactivation rates for these levels can also be obtained.

ISSN:0003-6951    

DOI:10.1063/1.1654655

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Measurements of magnetic domain velocity by domain transport methods in an epitaxial Y2.4Eu0.6Ga1.2Fe3.8O12film have yielded values as high as 2800 cm/sec with no sign of saturation. These measurements conflict with those reported recently by Callenet al., who deduced a saturation velocity of 1300 cm/sec from bubble collapse measurements made on films of the same composition. It is suggested that the discrepancy is due to the wall velocity reaching momentarily the Walker breakdown velocity in the bubble collapse technique, which then leads to a relatively immobile spin configuration similar to the one reported recently for hard magnetic bubbles.

ISSN:0003-6951    

DOI:10.1063/1.1654656

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Positive refractive‐index layers in LiNbO3and LiTaO3have been produced by a novel out‐diffusion technique. The index profiles for a variety of conditions are measured directly with an interference microscope. Low‐loss optical waveguiding on the surface of these crystals has been observed.

ISSN:0003-6951    

DOI:10.1063/1.1654657

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

Noncollinear mixing in GaAs has been used to obtain phase‐matched generation of the far‐infrared difference‐frequency radiation at 100.8 cm−1with TEA CO2lasers.

ISSN:0003-6951    

DOI:10.1063/1.1654658

出版商:AIP    

年代:1973

数据来源: AIP