Digital Moiré Phase-Shifting Interferometric Technique for Aspheric Testing

Abstract

Faster and more accurate optical aspheric testing methods are required in many technical fields. A digital moiré phase shifting interferometer (DMPSI) with partial compensation lens (PCL) is proposed. With digital phase shifting technique, only one shot of interferogram is required, so the system structure is simpler with lower sensitivity to the environmental vibration. PCL is designed to enlarge the measurement range of asphericity. A DMPSI prototype in Fizeau configuration has been developed. After calibration, spherical surface is tested with accuracy comparable to Zygo interferometer.