Patent ID: 7639363

Claim:
A spectrometer comprising: an input polarizer, including an input polarizer center point, an input polarizer axis through the input polarizer center point, and an input polarizer azimuth vector originating on the input polarizer center point and pointing substantially perpendicular to the input polarizer axis; an output polarizer, including an output polarizer center point, an output polarizer axis through the output polarizer center point, and an output polarizer azimuth vector originating on the output polarizer center point and pointing substantially perpendicular to the output polarizer axis, the output polarizer axis being substantially collinear with the input polarizer axis, thus defining a long axis with an input end proximate the input polarizer and an output end proximate the output polarizer, the long axis projecting through the input polarizer center point and the output polarizer center point, the long axis further defining an input polarizer orientation between the input polarizer azimuth vector and the long axis and an output polarizer orientation between the output polarizer azimuth vector and the long axis; a plurality of birefringent phase elements residing between the input polarizer and the output polarizer, including a birefringent phase element center point and a birefringent phase element azimuth vector originating on the birefringent phase element center point and pointing substantially perpendicular to the long axis, thus defining a birefringent phase element orientation between the birefringent phase element azimuth vector and the long axis; an input quarter wave switch positioned between the input polarizer and the plurality of birefringent phase elements, the input quarter wave switch having a center point and an input quarter wave switch azimuth vector originating on the input quarter wave switch center point and pointing substantially perpendicular to the long axis, thus defining an input quarter wave switch orientation between the input quarter wave switch azimuth vector and the lone axis; and an output half wave switch positioned between the output polarizer and the plurality of birefringent phase elements, the output half wave switch having a center point and an output half wave switch azimuth vector originating on the output half wave switch center point and pointing substantially perpendicular to the long axis, thus defining an output half wave switch orientation between the output half wave switch azimuth vector and the long axis, where the orientation of at least one element is changed, the at least one element being selected from a group consisting of the input quarter wave switch orientation, the output half wave switch orientation, and any of the birefringent phase element orientations to substantially reproduce Fourier components of frequency spectra of light passing fully through the spectrometer substantially parallel to the long axis.