Interlaced diffractive grating
An interlaced diffraction grating system and process are disclosed. The interlaced grating system includes an optical dispersive grating with alternating bands of unique grating densities wherein the number of unique grating densities is greater than or equal to two. The optical dispersive grating may be reflective or transmissive, and it may be fabricated by mechanical ruling, holography, or reactive ion etching of a binary mask. An interlaced grating allows additional utility for both point spectroscopic detection as well as hyperspectral imaging.
1. A line-scan hyperspectral imaging system comprising:
a first lens;
a slit;
a collimating lens;
an interlaced optical grating;
a second lens; and
a 2-dimensional detector array;
wherein the first lens is configured to collect light from a scene and focus onto the slit, the collimating lens is configured to collimate the light from the slit onto the interlaced optical grating, and the second lens is configured to focus the light dispersed by the interlaced optical grating onto the 2-dimensional detector array;
wherein the interlaced optical grating comprises alternating bands of at least a first grating band and second grating band, and the at least first and second grating bands have unique grating densities;
wherein the system further comprises a processor configured to extract optical spectra data from the 2-dimensional detector array corresponding to the bands of the interlaced optical grating, and concatenate N neighboring spectral bands to form N−1 spectra.
2. A method of performing a hyperspectral imaging comprising:
focusing, by a first lens, light from a scene onto a slit;
collimating, by a collimating lens, light from the slit onto an interlaced grating;
focusing, by a second lens, light dispersed by the interlaced grating onto a 2-dimensional detector array;
wherein the interlaced grating comprises alternating bands of at least a first grating band and second grating band, and the at least first and second grating bands have unique grating densities;
wherein the method further comprises a extracting, from the 2-dimensional detector array by a processor, optical spectra data corresponding to the bands of the interlaced optical grating; and
concatenating, by the processor, N neighboring spectral bands of data to form N−1 spectra.