Holographic Interferometry Techniques Using Photorefractives Crystals of Sillenite Family Bi_(12)SiO_(20) (BSO) and their Applications in Analysis of Surfaces

摘要

The Holographic Interferometry is a Non-Destrutive Testing of analysis on surfaces in basic research, technological and biomedical fields. However, the holographic interferometry techniques in real-time with conventional materials (silver halide emulsions, photothermoplastics...) present serious difficulties. The photorefractives crystals are presenting as a attractive holographic recording medium. The phenomenon that characterizes these crystals is the photorefractive effect, consists of the refractive index modulation through photo-induced and linear electro-optic effect, allows the register of holograms of phase. Also it presents advantages as in situ self-proceeding of the recording medium and its indefinite reusability, i. e., it does not present fatigue. Thus, the objective of this work is the development of a Holographic Interferometer that uses the Photorefractive Crystal of the Sillenite Family Bi~(12)SiO~(20)(BSO) as holographic recording medium. In this direction, we search to characterize BSO crystal determining some figures of merit in diffusive regime (without applied external electric field) and drift regime (with applied external electric field). The holographic techniques of metrology are presented in three methods: Real-Time Holographic Interferometry (RTHI), Double-Exposure Holographic Interferometry (2EHI), and Time-Average Holographic Interferometry (TAHI) had been studied with some applications in analisys of statics and dynamics processes on surfaces.