DUAL HOLOGRAM TECHNIQUE WITH ENHANCED SENSITIVITY FOR MEASUREMENTS OFWEAK PHASE OBJECTS

Conventional interferometric measurements of weak phase objects run in to serious accuracy problems due to low sensitivity and/or optical abe rrations. This paper describes an optical method, based on the dual ho logram technique, with enhanced sensitivity and with compensating for the optical aberrations. It provides a reliable acquisition of the pha se information from wide range of weak phase objects including high sp eed flow fields. The method was demonstrated by mapping the density fi eld of a small size axisymmetric supersonic jet as a representative we ak phase object.