Patent attributes
A measuring apparatus includes a pinhole mask, located on an object plane of an optical system to be measured, and having a plurality of pinholes for generating a spherical wave from a measuring light beam, and a diffraction grating for splitting the measuring light beam that has passed the pinhole mask and the optical system, in which Lg=m·Pg2/λ is met, where Pg is a grating pitch of the diffraction grating, λ is a wavelength of the measuring light beam, m is an integer other than zero, and Lg is a distance between the diffraction grating and an image plane of the optical system. The measuring apparatus detects an interferogram formed by interference between a plurality of the measuring light beams split by the diffraction grating. The plurality of measuring light beams includes an aberration of the optical system.
