Title

Spectral analysis of Bragg and non-Bragg orders in dynamic holography using photorefractive materials

Author

Akash Kota

Date of Award

2016

Degree Name

M.S. in Electrical Engineering

Department

Department of Electrical and Computer Engineering

Advisor/Chair

Advisor: Partha P. Banerjee

Abstract

The photorefractive effect is a nonlinear optical effect that refers to change in refractive index of a material when it is illuminated by light. When illuminated by an interference pattern of coherent light source, this PR effect is responsible for two-beam coupling in PR materials, sometimes leading to energy exchange between the beams. PR materials can also be used as holographic storage media. In fact, dynamic real-time holographic interferometry can be implemented using photorefractive materials. To achieve this, two beams, one called the pump and one called the object beam, are introduced onto a photorefractive material to write the hologram of the object. During the hologram writing process, these beams can couple in intensity and/or phase which thereafter are responsible for self-diffraction of these beams, and can also give rise to Bragg and non-Bragg orders. The information from the Bragg and non-Bragg orders plays an important role in determining the 3D information of the object. In this thesis, an exact study is performed to examine the spatial evolution of Bragg and non-Bragg orders in photorefractive iron doped lithium niobate for different types of beam profiles such as Gaussian and flattops using an angular plane wave spectral decomposition technique. For Gaussian beam incidence, it has been found that higher or non-Bragg orders shows evidence of mode conversion of incident beam profiles. The numerical technique developed in this work should be useful in determining the phases of the Bragg and non-Bragg orders which have applications in dynamic phase-shifting digital holography and holographic interferometry.

Keywords

Holographic interferometry, Beam optics, Three-dimensional imaging, Lithium niobate, Photorefractive materials, Optics, Electrical Engineering, photorefractive materials, dynamic holography, Bragg and non Bragg orders, lithium niobate, angular spectrum, phase shifting digital holography

Rights Statement

Copyright 2016, author

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