Curvature measurement of optical surface using digital holography

In this paper, an optical surface curvature measurement technique based on digital holography is proposed. Unlike the previous digital holographic methods, which only involve a small part of the measured data for parameter estimation, the proposed method adopts more of them using least square method. Hence, the analyzed result is not affected by data extraction direction and less sensitive to imperfect phase compensation. The proposed method is demonstrated with a sample of reflection mirror in laser resonator, and verified by comparing the measurement result with that of the white light interferometer.

Research highlights
► Existed digital holographic methods for optical surface measurement are discussed.
► Least-square method is introduced into digital holography.
► More data are utilized to increase the accuracy and reliability of results.
► No movement is required.
► Results are independent of pre-processing.