摘要:

Cowan's equations have been replaced by an equation giving the thermal diffusivity &agr; of a thin plate uniquely as a function of the measured quantities &Dgr; and &dgr;0, &Dgr; being the phase difference between the temperature variations at the two faces of the slab and &dgr;0the phase difference between the modulated heating beam and the nonheated face. A very simple approximate equation is also proposed for &Dgr;>1.

ISSN:0003-6951    

DOI:10.1063/1.1654272

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A thin‐film optical waveguide with self‐focusing caused by controlled distribution in the thickness was made of nitrocellulose and suspended in air. Undulation of the guided light beam was observed in the film, as well as in the self‐focusing optical fiber, when a He&sngbnd;Ne laser beam was injected at a place apart from the thickest center of the film. From this experiment, it has been shown that the transverse focusing effect in thin‐film optical‐wave transmission is obtained by the distribution in thickness of the film.

ISSN:0003-6951    

DOI:10.1063/1.1654273

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A method is described which allows the recording of an rf signal and its restoration at any time after a few microseconds following the writing. Once the signal is converted into a surface elastic wave on a piezoelectric substrate, an electron beam impinges upon the surface during a short time. A charge‐stored image of the signal is realized by the secondary electrons. Reading is achieved by means of a second current pulse which erases the surface charge distribution, exciting two elastic waves. One of them is the time‐inverted image of the signal. An attenuation of 63 dB has been measured at 30 MHz on quartz after a storage time of about 1 min.

ISSN:0003-6951    

DOI:10.1063/1.1654274

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

We report on the growth and the measurement of optical and optoacoustic properties of Tl3AsS4, a new single‐crystal sulfosalt material. It is transparent from 0.6 to 12 &mgr;m, has an optoacoustic figure of merit (relative to fused silica) of over 500 (at 0.6328 &mgr;m), and rather low acoustic losses.

ISSN:0003-6951    

DOI:10.1063/1.1654275

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A new method of deep‐level spectroscopy is demonstrated on ZnTe Schottky‐barrier diodes. Peaks in conductance measured as a function of temperature and frequency yield level depths and capture coefficients. A small‐signal theory is developed for numerical comparison to capacitance data, yielding level types and densities.

ISSN:0003-6951    

DOI:10.1063/1.1654276

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

Energy transfer from Tl+to Gd3+is reported in borax and phosphate glass. It was found that the6P7/2→8S7/2fluorescence of gadolinium could be increased manyfold when excited through1S0‐3P1absorption of Tl+. It is suggested that the energy from the thallium ion is transferred directly to the6P7/2state of gadolinium.

ISSN:0003-6951    

DOI:10.1063/1.1654277

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

The power threshold for optically induced bulk damage in sapphire is a sensitive function of the ellipticity of the incident beam shape. Experimental results are consistent with a simple self‐focusing theory.

ISSN:0003-6951    

DOI:10.1063/1.1654278

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

An inverse Lamb dip has been observed for infrared‐microwave two‐photon transitions in14NH3and15NH3. The signal was sufficiently strong to be observed on an oscilloscope with a detector time constant of 3 msec. The observations establish a method of measuring differences between laser frequencies and molecular absorption frequencies with high accuracy even if this absorption is outside of the tuning range of the laser lines. A double resonance experiment involving the two‐photon inverse Lamb dip has also been conducted.

ISSN:0003-6951    

DOI:10.1063/1.1654279

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

A very intense gas breakdown spark has been extended to a continuous arc in argon using a focused cw CO2laser. To achieve cw breakdown, the focal volume of a mirror focusing a high‐power CO2laser was preionized by a single pulse from a CO2TEA laser. The electron density created by the pulsed laser is sufficient to start the cw plasma. This letter reports accurate measurements of pulsed thresholds as well as preionized cw thresholds for breakdown in argon. Also, a study of the time development of the cw plasma is presented.

ISSN:0003-6951    

DOI:10.1063/1.1654280

出版商:AIP    

年代:1972

数据来源: AIP

摘要:

X rays induced by 20‐MeV oxygen ions have been used to search for trace quantities of lanthanum on the surface of a NaCl crystal. The results demonstrate the sensitivity of the method to small quantities of heavy elements present on low‐Zmatrices.

ISSN:0003-6951    

DOI:10.1063/1.1654281

出版商:AIP    

年代:1972

数据来源: AIP