Ultra-compact snapshot imaging fourier transform spectrometer
AssigneeArizona Board of Regents on Behalf of the University of Arizona
InventorMichael W. Kudenov
Life of this patent
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Abstract
Snapshot imaging Fourier transform spectrometers include a lens array that produces sub-images that are directed through a birefringent interferometer in orthogonal polarization eigenstates that acquire an optical path difference. Interference patterns based on this OPD can be Fourier transformed to obtain a spectral image. In some examples, polarizing gratings provide a spatial heterodyne frequency and offset the spectra.
Claims19
An interferometer, comprising, from object-wise to image-wise along an axis:
- a lens array configured to produce a plurality of sub-images of an object based on associated sub-image light fluxes;
- a birefringent prism configured to produce a spatially varying optical path difference (OPD) between orthogonal polarization states associated with the sub-image light fluxes;
- a polarization analyzer situated to project at least a portion of orthogonal polarization states of the sub-image light fluxes to a common polarization state;
- and
- an array detector situated to receive the projected sub-image light fluxes.
A spectral imaging method, comprising:
- directing a plurality of sub-image light fluxes associated with an object to a birefringent prism so as to produce optical path differences between orthogonal states of polarization of the sub-image light fluxes;
- transmitting the sub-image light fluxes with the optical path differences to a polarization analyzer;
- and
- recording intensity patterns based on the polarization analyzed sub-image light fluxes;
- and
- processing the recorded intensity patterns so as to produce a spectral image of the object.
A spectral imaging apparatus, comprising, along an axis from an object:
- a lens array configured to produce a plurality of sub-images of an object associated with sub-image light fluxes;
- a polarization generator configured to polarize the sub-image light fluxes;
- a birefringent prism pair situated to receive the polarized sub-image light fluxes such that the sub-image light fluxes propagate in the birefringent prism pair in at least two eigenpolarizations;
- a quarter wave retarder situated to receive the sub-image light fluxes from the birefringent pair and produce corresponding circularly polarized light fluxes;
- a polarization grating situated to receive the circularly polarized light fluxes and produce corresponding diffracted light fluxes;
- an array detector configured to record the diffracted light fluxes;
- and
- a processor configured to produce a spectral image based on a Fourier transform of the diffracted light fluxes, wherein the Fourier transform exhibits a spatial heterodyne frequency based on a period of the polarizing grating.
Dependencies are inferred from the claim text.