Linear response, multi-order grating interferometry using a reversal shearing imaging system

Linear response, multi-order grating interferometry is proposed to measure grating displacement. The system, a combination of a reversal shearing interferometer and an imaging system, enables calculating multi-order, integrated intensity signals with a linear waveform response. A theoretical multi-order model for the linear response signal analysis is presented with a Fourier series expansion. The results of the experiment, which prove the validity of the theoretical model, indicate a linear response to displacement with a linearity of 98.7% and a resolution of 10 nm. We conclude that the proposed method enables the development of a new class of potent linear response grating interferometry for displacement metrology.