Brillouin scattering in anisotropic crystals is reviewed. First is given the difference in the scattering angles between isotropic media and birefringent crystals. Second, the Brillouin scattering cross section is derived for hexagonal crystals with the crystal symmetry of 6mm, 6m2, 622, or 6/mmm. Scattering cross section in CdS is calculated for the scattering by the transverse acoustic waves propagating perpendicularly to the c axis with the particle displacement along the c axis, as an example. A generalized expression of the scattering cross section derived by Nelson, Lazay, and Lax is given with including the direct and indirect photoelastic effects and also including the rotational contribution. Finally, recent developments in the study of acoustoelectric effect by means of Brillouin scattering are summarized with main emphasis on CdS and ZnO.
The process of film deposition by rf sputtering was investigated by observing the deposition rate and the thickness of the cathode dark space as a function of argon pressure in an rf diode sputtering system with a spherical titanium cathode, which avoids any edge effect on the target. The deposition rate increased with pressure in the region from 3×10-3 to 10-2 torr, but decreased as the pressure was raised above 2×10-2 torr. It is found that these phenomena can be explained by taking into account the ion energy bombarding the target and the transport process of the sputtered atom.
Experimental study on the pulsed-Raman spectroscopy has been performed to measure the Raman scattering cross sections for gaseous molecules, including important air pollutants. The optimum conditions for light collecting ability have been analysed for four different optical systems, and the convex lens system was found to have the highest collecting efficiency for the focused laser beam. Furthermore, the pulse-gate photon counting method has been developed for detecting extremely low-intensity, pulsed light signals. From an analytical study, it is concluded that this method gives better performance as compared with the con-ventional techniques. The Raman scattering cross sections for 15 gaseous molecules relative to that of N2 have been measured at 3371 Å using a pulsed N2 gas laser. Acceptable agreement, within experi-mental accuracy, exists for our data with previously published data using visible light sources.
An apparatus which aims a camera towards a definite point with great precision while travelling along a straight line has been deve-leped. The principle, Construction and perfor-mance of the apparatus are described.