General theory of Raman and Brillouin instabilities in piezoelectric materials with strain dependent dielectric constant

In the present communication few problems in the area of Raman and Brillouin instabilities in piezoelectric materials with strain dependent dielectric constant (SDDC) was proposed. The stimulated Brillouin scattering and resulted instability provide a unique tool for the study of acoustic domains since it provide a mean of following the evolution of a particular frequency component propagating in particular directions. The stimulated Raman scattering and consequent instability is used mostly as a tool for studying the vibrations energy level of molecules’ and lattice vibrations of the optical branch in the crystals. The intense experimental and theoretical efforts of the past few years in this area have yielded a beautiful return in our basic knowledge but in addition it has opened the way to several classes of new devices with high efficiency and power in different interested frequency regions. The success on both a basic and practical plane offers promise for continuing useful results and increased knowledge from future work in this area. A detail review of the work of wave interactions (linear as well as nonlinear) in solid state plasmas has been made by several workers. A state important advancement in the study of solid v plasmas has brought about the realization that many of the physical characteristics of solid can be explained in terms of the elementary excitations that may be supported by the given solid. One of the most important properties of and electron plasma and or hole plasma is that can support a great variety of collective modes. A number of workers have studied theoretically and experimentally. The excitations of various collective mode in semiconductors. The impetus of `research stems from its relation to the fundamental properties of solids as well as the possibility of its technological utilization in solid state devices. Various types of non linear wave interactions occur in semiconductor plasmas (e.g. parametric modulational, stimulated brillouin and Raman scatterings) under suitable condition s giving rise to appreciable growth rates. Key-Words: Theory, Raman, Brillouin, Dielectric constant Introduction Classically the non linear interactions can broadly be called as those interactions in which lossless (or low loss) non linear energy storage mechanism couples a number of normal modes at different frequency’s in a generalized dynamic system. It is possible to feed energy into a system and to excite non linear instabilities. The feeding of energy to the system is called pumping. The non linear interactions can be grouped into three broad categories:1. Basically non linearizable problems. 2. Wave particle interactions. 3. Wave wave interactions [1] [2] It was concentrated that attention towards the non linear wave wave interaction in piezoelectric materials with SDDC. * Corresponding Author: E-mail: [email protected] Light Scattering Basics This section is a brief introduction into the basic principles of light scattering. While the derivation of scattering theory on the basis of quantum field theory is possible, herein the scattering medium as well as the light is treated classically, leading to practically the same results within the scope of this thesis. Of course there are light scattering effects, as for example in the well-known Raman scattering technique, which deals with rotational and vibrational transitions of single atoms or molecules, i.e., effects in a quantum length scale, that must be treated (at least partially) quantum mechanically. However, this thesis deals with the investigation of phonons by Brillouin light scattering in condensed Basics and Brillouin Light Scattering matter. Thus the investigated phonons are classical waves with wavelengths in theorder of some nanometer Research Article [Saxena, 2(11): Nov., 2011]