Defect detection based on a lensless reflective point diffraction interferometer

We propose a defect detection system to identify phase defects on optics based on a lensless reflective point diffraction interferometer (LRPDI). The optics under test are illuminated by a collimated beam to produce a signal wavefront carrying the defect information, and then the signal wavefront is recorded in a high carrier interferogram using the LRPDI. By lensless imaging, amplitude and phase defects, as well as the accurate phase of a phase defect, can be identified. The simulation and experiment demonstrate the success of the proposed system in detecting phase defects, and its high-accuracy and high-resolution dynamic detection abilities are verified.