Glancing angle deposited thin films and their applications in laser systems

Abstract

ABSTRACT Glancing angle deposition (GLAD) is a novel way to produce nanostructural thin films with engineered porosity, and it is possible to make new optical components in laser systems. In this paper, ZrO 2 , SiO 2 and TiO 2 thin films were grown by electron beam evaporation with GLAD technique. Different mi crostructures were observed. The optical properties, such as transmittance and refractive index were characterized. As application of the GLAD thin films, several optical components were designed and fabricated, such as graded-index rugate filter, br oadband antireflection coating and phase retardater for visible and near infrared laser systems. Finally, laser-induced damage threshold were measured and discussed. Key Words: thin films; glancing angle deposition; nanostructure; optical component; laser-induced damage threshold 1. INTRODUCTION Recently, glancing angle deposition (GLAD) technique has attracted considerable attention for de signing the novel morphology of the nanostructured films [1, 2]. This technique employs substrate inclination and substrate rotation, which were driven by two step motors controlled by a computerized program [3, 4]. As a result of enhanced shadowing effect and limited atom diffusion during film growth, the GLAD thin films have high porosity and anisotropic growth behavior . GLAD technique has been shown to be capable of producing films with various microstructures, such as vertical columns [5], helix [6], which is hardly obtained from the normal incidence vapor deposition. Thus, many novel physical and chemical properties of thin films can also be easily engineered. In this paper, ZrO