Contemporary Holography

ACoherence of Optical waves

A.1 INTRODUCTION

The coherence of optical beams play very important role in obtaining interference pattern of two light beams and more importantly for getting good quality holograms. In general, the coherence property is directly linked to the origin of light beams from the source. For example, in case of laser beam generation, the life time of atoms in meta stable state is direcly related to coherence length of laser beam. Consider a wavefront with its electric field component given by E=E0sin(kz−ωt+ϕ) and after some time i.e at (t=t+Δt) if this wavefront still remains sinusoidal with same phase then these two wavefronts are coherent. Thus at time t and (t+Δt) if two wavefronts have same phase relationships then ...