0000000000012080
AUTHOR
P. Cavaliere
Soret Effect In Forced Rayleigh-scattering
In forced Rayleigh scattering of mixtures or suspensions the temperature gratings generate, by the Soret effect, concentration gratings that may be very important since they produce both a phase and an amplitude grating superimposed on the principal one. The experimental evidence of their influence was given by Thyagarajan and Lallemand using a mixture of carbondisulfide and ethanol. In this paper we study the temporal behaviour of the concentration grating versus the sample properties and its effect on the detected diffracted beam. Explicit expressions are given for the output intensity taking into account both the generated amplitude and phase gratings.
Electrooptic beam deflection with latex
The use of latex in electrooptic devices is proposed. The static non linearity coefficient is shown to be approximatively 200 times the optical one. The theory of a beam deflector is developed and an explicit expression is given for the deflection angle versus the physical parameters of the sample Utilisation de suspensions aqueuses de latex dans un dispositif electro-optique. On montre que le coefficient statique de non-linearite devrait etre 200 fois plus eleve que le coefficient optique. Application a un deflecteur optique
Laser induced thermal profiles in thermally and optically thin films
The temperature field generated by the weak absorption of a gaussian laser beam in an optically and thermally thin film bounded by two transparent plates is discussed. An analytical solution of the problem is presented together with an algorithm for the numerical integration. The influence of the finite thermal conductivity of the plates is shown in an example.
Dislocations in AIIIBVI single crystals
High densities of planar defects are evidenced in various AIIIBVI layer compounds by systematic electron microscopy observations with the dark-field weak-beam image technique. Several samples are analyzed, as obtained from different crystal ingots of InSe grown by the Bridgman-Stockbarger method, and some GaS and GaSe single crystals grown both, from the melt and from the vapour. The observed defects are identified mainly as screw and edge dislocations, the orientation of which is obtained in some cases by the analysis of the Moire fringes. Dislocation densities ranging between 108 and 1010 cm−2 are measured, not uniformly distributed in the various regions of each sample. Finally, the obse…