Recent developments of semiconductor lasers are described. Emphasis is placed on GaAs lasers, which have been developed extensively. Behaviors of GaAs Double Heterostructure lasers are fairly well understood, and their characteristics are becomming sufficient for many applications.
The statistical continuum theory by de Gennes and others is introduced and applied to fluctuation and relaxation phenomena both in the nematic and isotropic phases of nematic liquid crystals. Experimental results such as light scattering, shear wave attenuation, nuclear magnetic relaxation, ultrasonic absorption and dispersion are reviewed and discussed consistently by the unified theory.
Magnetoelastic wave propagation through a thin magnetic plate with surface metallization is discussed. The dispersion relations for transverse magneto-elastic modes are derived in the case of metal films covered on one face only and on both faces. The dispersion curves are evaluated numerically for two kinds of plate thickness and for different magnetic field intensities. It is shown that the nonreciprocal transmission due to interaction between the elastic and magnetostatic modes occurs for surface metallization on one face only but disappears when both faces are metallized. The influence of a metal film for magneto-elastic surface wave propagation in a semi-infinite medium is also discussed.
The effective second-order nonlinear coefficients in the noncentro-symmetrical biaxial crystals are formulated in a general way as functions of their crystal symmetry and directions of propagation of light in the crystal. This treatmentis applied to the iodic acid (HIO3) crystal, which belongs to the 222 class and has good optical qualities and is known to have a pronounced nonlinear optical coefficient. Sellmeier's equations for this crystal were also derived to give the refractive indices between 0.45μm and 1.2μtm based upon the measured data of Kurtz et al. The phase matching conditions for second-harmonic generation (SHG) and parametric oscillation at various wavelength regions were calculated dy using these equations, and optimum operating conditions for SHG of 1.064μm-Nd: YAG laser and 0.532μm-pumped parametric oscillation are discussed analytically in terms of the effective second-order nonlinear coefficients as formulated in this paper.
C-V characteristics of MOS diode with SiO2 film by glow discharge reaction between organic silicate and oxygen gas are reported. C-V characteristics of MOS diode with SiO2 film prepared by glow discharge reaction alone, depend on frequency, but show no hysteresis. Fre-quency dependence of C-V characteristics decreases and its hysteresis appears with the formation of thermally grown thin oxide on the Si surface. The hysteresis disappears with the densifica-tion of SiO2 film prepared by glow discharge reaction in a nitrogen atmosphere. MOS diode with SiO2 film prepared by glow discharge reaction of thickness of about 2, 000 A densified in a nitrogen atmosphere at 600°C over a thermally grown SiO2 film whose thickness is about 100A shows no frequency dependence and no hysteresis in its C-V characteristics. For such a diode Nrs is about 5.5±1010 cm-2. It seems that the influence of bombardment on a Si surface by ions and electrons during the deposition of SiO2 film by glow discharge reaction is much less than that of conventional sputtering.
In KCl tablet crystals formed by compressing KCl powder, the authors propose newly a confusion factor (CF) by which the shape of the grain boundary can be related in terms of the two adjacent grains. Firstly the visual shape of the grain boundary (straight, curve and zigzag) is denoted by an intuitive CF:F. Secondly the mean total CF:A and an individual CF : a are newly defined as a=4 trg (θ, π/2) and A=1/2(a1+a2), where trg denotes a periodic triangular-wave function and θ is the angle which etched pattern in an individual grain makes with the grain boundary. Finally it is found that observed distribution of the F's for miscellaneous configuration of the grains are well explained in terms of A and a.