Detecting Phase-Type Defects of Transparent Samples Using Infrared Phase-Shifting Shearing Interferometer

摘要

A shearing interferometer based on the use of a low-coherence short-wave infrared source, two Savart shear devices, and the phase-shifting technique is proposed in this research. It is free of speckle-noise and robust to environmental perturbations, and it is capable to identify phase-type defects in the inspected sample using a gradient image obtained by the phase-shifting technique. This paper introduces the configuration, measurement theory, experimental setup, and experimental results of the proposed interferometer. The results confirm the capability of defect detections of the proposed interferometer.