Patent ID: 8786863

Claim:
A transmitted wavefront measuring method comprising the steps of: emitting light from a light source onto an object to be measured to receive interfering light transmitted through the object to be measured and a diffraction grating on a light receiving portion disposed at a predetermined distance from the diffraction grating to measure an intensity distribution of the interfering light; performing a Fourier transform of the intensity distribution of the interfering light to calculate a frequency distribution; and obtaining a transmitted wavefront of the object to be measured based on a primary frequency spectrum in the frequency distribution, wherein the step of obtaining the transmitted wavefront comprises the steps of: performing an inverse Fourier transform of the primary frequency spectrum with reference to a grating frequency of the diffraction grating to calculate a complex amplitude of the interfering light, and obtaining the transmitted wavefront, including a focus component, corresponding to a difference between the primary frequency spectrum and the grating frequency.