Volume 14, Issue 4, 15 February 1969
Index of content:
EFFECT OF THE NON‐EQUILIBRIUM CARRIERS ON THE TEMPERATURE HYSTERESIS OF THE PHASE TRANSITION IN SbSI14(1969); http://dx.doi.org/10.1063/1.1652739View Description Hide Description
The illumination of the SbSI crystal in the range of its intrinsic photosensitivity results in the change of the temperature hysteresis value of the phase transition. This effect may be accounted for by the dependence of the surface energy of the nucleus of the new phase on the carrier density in the crystal.
14(1969); http://dx.doi.org/10.1063/1.1652740View Description Hide Description
An experiment to record a holographic motion picture is described. The source of illumination is a cw ruby laser operated in the repetitively Q‐switched mode. The film was recorded at the rate of 20 frames per second on 100 ft of 70‐mm film, transported by a conventional 70‐mm sequential‐still camera. The subject of the movie was a group of tropical fish.
14(1969); http://dx.doi.org/10.1063/1.1652741View Description Hide Description
Transfer of acoustic surface waves between two noncontacting surfaces by means of passive, co‐directional piezoelectric coupling is achieved in LiNbO3. Minimum coupling loss is less than 3 dB. When the surfaces are maintained parallel, periodic variation of insertion loss with coupling length is observed. Measurements are in close agreement with predictions using coupled mode theory. A 100‐MHz delay line with a mechanically variable, nondispersive differential delay of 6.1 μsec and a total insertion loss less than 17 dB which utilizes this coupling mechanism is reported.
14(1969); http://dx.doi.org/10.1063/1.1652742View Description Hide Description
It is shown that oscillation in Ar+ on the 4881‐Å line produces polarization source terms in the region of the 5147‐Å oscillation. These source terms may profoundly influence the mode spectra and the power output of that line. Certain earlier experimental results may be understood in terms of these concepts. We also give further support to the presented mechanism through new experiments.
14(1969); http://dx.doi.org/10.1063/1.1652743View Description Hide Description
A model is presented for the measurement of the voltage drop across a plasma anodized germanium film. This model proposes that the potential at the plasma—oxide interface is controlled by the plasma. From this model the anodization constant of germanium has been determed to be 31 Å/V.
14(1969); http://dx.doi.org/10.1063/1.1652745View Description Hide Description
14(1969); http://dx.doi.org/10.1063/1.1652746View Description Hide Description
Reversible phase holograms have been made on thin films of MnBi by Curie‐point writing. Magnetic holograms are formed when the interference pattern, created by conventional holographic techniques, heats the film above its Curie temperature, causing a magnetic domain pattern that corresponds to the interference pattern. The magnetic hologram can be nondestructively read out, without the use of polarizers or analyzers, by means of either the Faraday or Kerr magneto‐optic effect. The hologram can be erased by application of a magnetic field.
14(1969); http://dx.doi.org/10.1063/1.1652747View Description Hide Description
Twenty‐four lasing lines have been found in an H2S laser in the range 33 to 225 μ, three lines in SO2 at 141, 151, and 215 μ, and two lines in OCS at 123 and 132 μ. Comparing H2S to H2O, the pulse power outputs are about equal and the lines about as numerous. However, while the H2O lines essentially lase during the exciting 5‐μsec current pulse, the H2S lines turn on about 20–30 μsec after the 5‐μsec current pulse and last for 20 to 100 μsec.
14(1969); http://dx.doi.org/10.1063/1.1652749View Description Hide Description
A frequency modulation which is monotonic in time over a portion of an optical pulse can be utilized together with a dispersive delay line to obtain temporal compression of the pulse envelope. Short pulses (picosecond range) passed through an optical Kerr liquid receive a self‐phase‐modulation which exhibits a frequency sweep in the region of maximum intensity, the slope in time being proportional to the propagation distance. Frequency spreads of the order of 103 cm−1 are obtainable and hence significant compression ratios should be possible, giving rise to very short pulses in the range of 10−14 to 10−13 sec.