(1977) Schad, Hanspeter; Lassmann, Kurt; Zeile, Heinrich
Fine structure, level splitting, and relaxation times of the acceptor ground state in cubic semiconductors can be deduced from ultrasonic attenuation. By the application of a magnetic field it is possible to vary the coupling strength and the number of acceptors on speaking terms with the ultrasonic wave. Making use of this possibility, we have determined directly effective coupling constants for relaxation attenuation and the temperature dependence of the critical intensity for saturation of the resonant interaction. Results obtained for p-type GaAs and Si are discussed in comparison with analogous results for glasses.
Laser photography has been found to be a very useful and powerful tool for many applications. The interpretation of the fringes obtained is very much easier than for holography. Speckle techniques for strain, displacement and vibration analysis were found to be very powerful aids. The requirements on coherence of the light source used are moderate. High-resolution, low-scatter film or plates can be used to record the speckle patterns (Kodak or Agfa Scientia).