Growth and characterization of some organic and inorganic nonlinear optical (Nlo) crystals

Abstract

The fascinating field of nonlinear optics (NLO) has a direct bearing on technology and has brought about enormous changes in the fields of Science and Engineering. In today s context of demand for real time control and communication, NLO materials play a vital role in the fabrication of electro-optic modulators, which convert an electric signal to an optical one for transmission through a fiber optic cable. The application of NLO materials includes fiber optics, image applications using photo refractive crystals, frequency multipliers and mixers, parametric oscillators and optical switches. Because of the effectiveness in generating new frequencies from existing lasers via harmonic generation and sum and difference frequency generation, there has been a wide search in recent years to identify suitable materials for such processes. It is expected that these materials should (i) be resistant to optical damage, (ii) have high mechanical hardness, (iii) exhibit good thermal and chemical stability, (iv) be capable of being grown in useful size and (v) have the appropriate phase-matching properties. The organic NLO crystals have higher nonlinear response compared to inorganic crystals. But the inorganic crystals are more thermally stable than the organic counterparts. In the present work, some organic and inorganic nonlinear optical crystals were grown by solution growth technique and were characterized. This thesis consists of nine chapters. The first chapter gives a brief introduction to crystal growth techniques and in particular, the growth from solution. Overview of historical perspectives of nonlinear optical phenomenon and criterion for NLO crystals are also discussed in this chapter. A discussion on new NLO materials built from organic, semiorganic and inorganic materials and their applications are also included.The second chapter deals briefly on the various analytical instrumentation techniques which are very important in understanding the properties of the crystal.