Patent ID: 7221454

Claim:
An instrument for measuring the complete polarization state of light over a spectral bandwidth, the instrument comprising: a source for producing an incident light beam ( 41 ); at least two diffraction gratings ( 42 , 44 , 46 , 48 ), said gratings having a spatial frequency selected to produce a zero order diffracted beam and at least one non-zero order diffracted beam, the gratings positioned such that the first grating ( 42 ) intercepts the incident light beam ( 41 ) and subsequent gratings ( 44 , 46 , 48 ) intercept the zero order beam ( 43 , 45 , 47 ) transmitted by a grating to produce at the gratings ( 22 , 44 , 46 , 48 ) at least four non-zero order diffracted beams ( 49 , 50 , 51 , 52 ); photodetector arrays ( 57 , 58 , 59 , 60 ) positioned to intercept at least four of the non-zero order diffracted beams; and means responsive to the photodetector arrays ( 57 , 58 , 59 , 60 ) for calculating the polarization state of the incident light beam ( 41 ) over the wavelength range of the light.