Measurement error estimation and calibration for on-line detection phase variations in the laser-induced damage...

The amplitude and phase distributions of reflection or transmission light are locally disturbed by damage regions. The damage state of optical components under successive laser irradiation can be evaluated according to the phase variation of a transmitted beam. The measurement accuracy of phase information related to the phase-unwrapping method is a critical factor for evaluating the damage state. This study analyzes and compares the performance of two important phase-unwrapping methods for detecting on-line large damage sites based on optimal modified lateral shearing interferometry. Meanwhile, the system stability and the measurement repeatability are also validated according to the retrieved phase pattern, which is beneficial to estimating the measurement accuracy. Experimental results of optical films are also presented and discussed to verify the feasibility of the estimation method utilized and the recommended phase-unwrapping method for on-line detection of the laser-induced damage growth features.