Effect of binary pseudo-random grating and step on system transfer function calibration of interferometric measurement system

Using standard phase structures with high quality is the precondition for accurate calibration of system transfer function(STF) of the interferometric measurement system, which guarantees the accurate measurement of the optical wavefront or surface informations in the mid and high spatial frequency bands. Two types of typical standard phase structures are simulated and analyzed, one is the binary pseudo-random(BPR) grating, and the other is the step. According to the comparison of the effect of the fabrication imperfections on the measurement of system transfer function between the BPR grating and the step, more reliable calibration of the STF in mid and high spatial frequency bands can be obtained using BPR grating as the standard, when the error parameters are the same. The changes of the corresponding PSD are also analyzed, when the BPR grating is oversampled or undersampled by CCD, the PSD will decline with the frequency, and the effect of sampling on the STF calibration can be removed by modifying the height distribution of the theoretical BPR grating.