Micropolarizer Phase-shifting Array For Use In Dynamic Interferometry

Abstract

This work examines a novel method of dynamic single frame interferometry. In this dynamic approach to phase shifting measurements, steps are taken to combat performance degradation due to environmental factors such as air turbulence and vibration. We explore the system functionality and performance, and examine some of the limiting factors using this technique such as effects due to imperfect system components, irradiance variations and sensitivity of the instrument accuracy based on calculation methodology. We present the errors associated with these various aspects of the system and show the majority cause phase calculation errors less than 0.005λ P-V to the calculated wavefront. This new approach involves the placement of a micropolarizer phase-shifting array directly onto a CCD camera which allows the construction of a dynamic single frame interferometric system. Hardware and manufacturing preparations such as inspection, positioning and alignment are discussed. Experimental results of system performance are combined with mathematical simulations to provide a performance baseline. We present experimental results showing the effects of averaging on measurement data, which results in a reduction of fringe print-through errors associated with a combination of many of the system error sources.