Patent ID: 9423306
Filing Date: 2016-08-23
CPC Classification: G01B,G01J,G03F

Claim Text:
1. A method of measuring characteristics of a wavefront of an incident beam having a phase front, the method comprising: providing a transmission mask; providing an imaging device having a detector plane; passing a portion of the incident beam through the transmission mask; propagating the portion of the incident beam passing through the transmission mask over a predetermined distance; forming an interferogram at the detector plane of the imaging device; detecting the interferogram using the imaging device; Fourier transforming the interferogram to provide a frequency domain interferogram; selecting a subset of harmonics from the frequency domain interferogram; individually inverse Fourier transforming each of the subset of harmonics to provide a set of spatial domain harmonics; extracting a phase profile from the set of spatial domain harmonics; removing phase discontinuities in the phase profile; rotating the phase profile; and reconstructing the phase front of the wavefront of the incident beam.