Abstract: A measuring apparatus measures an optical performance of a test optical element and includes a diffraction grating configured to emit diffracted light, an image sensor configured to capture an interference pattern formed by the diffracted light, and a controller configured to move the at least one of the diffraction grating and the image sensor in an optical axis direction, to capture a plurality of interference patterns before and after movements, and to calculate a light-condensing position based on a spatial frequency of a plurality of interference patterns and a moving amount.

Abstract: A Talbot interferometer includes a diffraction grating, an image pickup device, a moving unit configured to move at least one of the diffraction grating and the image pickup device in an optical axis direction of the test object, and a computer configured to adjust a position of the at least one of the diffraction grating and the image pickup device using the moving unit so that a Talbot condition can be met, based on a spatial frequency spectrum obtained from a plurality of interference fringes captured by the image pickup device while moving the at least one of the diffraction grating and the image pickup device using the moving unit.

Abstract: A Talbot interferometer includes a diffraction grating, an image pickup device, a moving unit configured to move at least one of the diffraction grating and the image pickup device in an optical axis direction of the test object, and a computer configured to adjust a position of the at least one of the diffraction grating and the image pickup device using the moving unit so that a Talbot condition can be met, based on a spatial frequency spectrum obtained from a plurality of interference fringes captured by the image pickup device while moving the at least one of the diffraction grating and the image pickup device using the moving unit.