Growth and characterization of glycine based organic and semiorganic nonlinear optical crystals

Abstract

The present investigation deals with the growth and characterization of glycine based organic and semiorganic nonlinear optical crystals. The majority of the early nonlinear optical materials were based on inorganic crystals. More recently, however, focus has shifted toward organic molecules due to the much greater design flexibility in molecular compounds, which allows for a fine tuning of the microscopic properties and thus the linear and nonlinear optical behavior of the materials. Nonlinear optical (NLO) materials have attracted increasing attention due to their wide applications in the area of laser technology, optical communication, harmonic generators and data storage technology. The aim of the materials scientists and crystal growers is discovering new materials, growing the new materials and developing the materials from the existing one. This thesis is aimed to grow new organic and semiorganic crystals for nonlinear optical applications. The history of crystal growth and development, various methods in crystal growth and the fundamental features of nonlinear optics were explained elaborately in one part of the thesis. Nonlinear optical property was studied by Kurtz powder technique and its efficiency was compared with the efficiency of well known KDP crystal. The thermal analysis such as thermogravimetric and differential thermal analysis reveal that the grown triglycine calcium dibromide crystal has high melting point. Thermal stability of the crystal was analyzed by thermogravimetrical and differential thermal analysis. Mechanical properties such as yield strength and fracture toughness, brittleness index were studied from Vicker s microhardness testing. Further it was characterized by dielectric and etching studies in order to determine dielectric constant and investigate structural defects present in the crystal respectively. Thus, several organic and semiorganic nonlinear optical crystals were grown at room temperature and their properties were investigated. newline