摘要:

The extent of the lasing medium along the jet axis in a continuous chemical laser is variable under changes in the jet temperature, pressure, velocity, reactant concentration, etc. The laser cavity must be readily tunable to accommodate the changes in lasing length in order to maintain maximum multimode laser power operation in a high‐Fresnel‐number cavity under variation in the jet parameters. In addition, as an aid in understanding laser performance, it is desirable to have the means to determine the multimode laser intensity distribution in the lasing region for various conditions in the jet. Techniques are presented to determine the optimum optic axis position for maximum multimode power operation, and to measure the intensity distribution along the jet and extent of the lasing medium. A flat and spherical mirror tuned during laser operation determine peak laser power position and the lasing length of the jet (typically 1. 6 in. in N2flows). Axial local power surveys are made with this same cavity array coupled with a movable aperture which limits lasing to a small fraction of the total lasing region. A visual display of lasing length and the power distribution pattern along the jet, both axial and off‐axis, is obtained by coupling power out of one of a pair of optical flats into a lucite block.

ISSN:0003-6951    

DOI:10.1063/1.1654093

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Hydrogen fluoride laser emission has been observed following flash photolysis of ethylene and tetrafluorohydrazine at elevated temperatures in a Vycor laser tube. The observed emission includes onlyv=1→0 transitions; we believe this emission is caused by HF elimination from a chemically activated molecule formed by addition to the ethylene double bond.

ISSN:0003-6951    

DOI:10.1063/1.1654094

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A new type of image storage and display device is described in which the image is stored by means of a longitudinal electro‐optic scattering effect in ferroelectric ceramics. The stored image can be viewed directly or projected onto a viewing screen by using transmitted or reflected, polarized or unpolarized, white or monochromatic light. The device has the capability of selective erasure of part or all of the stored image.

ISSN:0003-6951    

DOI:10.1063/1.1654095

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

The Al metallization of integrated circuits is known to dissolve ½% or more Si, but the ultimate location of this Si has been uncertain. An electron microprobe operated at low beam energy so as to penetrate only the upper portion of the metallization was used to follow the movement of dissolved Si on cooling after the ``forming'' heat treatment. Dissolved Si substantially less than a diffusion length from the substrate was found to regrow there; elsewhere the Si forms precipitates in the Al matrix, preferentially near the free surface of the Al.

ISSN:0003-6951    

DOI:10.1063/1.1654096

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

The effect of the mechanical constraints exerted by coatings upon electromigration in thin films is evaluated on the basis of known pressure effects upon diffusion.

ISSN:0003-6951    

DOI:10.1063/1.1654097

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A study of the lasing and spontaneous emission fromp+‐n‐n+heterojunction lasers with lightly dopedn‐type active regions shows that the stimulated emission is not due to a simple band‐to‐band recombination process. It is further shown that the 300 K gain coefficient dependence on the junction current differs greatly from that predicted on the basis of band‐to‐band lasing involving a parabolic density‐of‐states distribution.

ISSN:0003-6951    

DOI:10.1063/1.1654098

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A new method is described for operationally defining a ``random'' spectrum as used in channeling studies of nuclear backscattering. The method is reproducible to 1%. A detailed analysis is made for the case of He4ions backscattered from silicon crystals. Corrections are determined so the ``random'' spectrum approximates that from an amorphous layer to within ± 1%.

ISSN:0003-6951    

DOI:10.1063/1.1654099

出版商:AIP    

年代:1972

数据来源: AIP