Compact optical spectrometer

摘要

A spectrometer employs multiple filters having complex filter spectra that can be generated robustly from received light over short optical path lengths. The complex filter spectra provide data that can be converted to a spectrum of the received light using compressed sensing techniques. The result is a more compact, easily manufactured spectrometer.

主权项

1. A spectrometer comprising:
a frequency filter, having a set of spatially separated regions, each region receiving light and modifying the light according to a set of different filter spectra each defining a frequency-dependent attenuation of the received light to provide a corresponding set of filtered light beams each associated with a different filter spectra, each filtered light beam of the corresponding set of filtered light beams providing light scattered by substantially only one of the spatially separated regions; a broadband light detector receiving the set of filtered light beams to provide a corresponding set of independent measures of each filtered light beam; an electronic computer executing a program stored in non-transient memory to receive the independent measures of the filtered light beams to generate a spectrum derived from the set of independent measures, the spectrum indicating intensity as a function of frequency for different light frequencies over a range of frequencies wherein the electronic computer configured to reconstruct the spectrum from the independent measures by finding a solution to an undetermined system of equations under an assumption of sparseness; wherein each different filter spectra is a broadband spectrum with substantially non-periodic variations in value as a function of frequency; wherein the frequency filter provides a planar light transmitting substrate extending in a plane in two dimensions perpendicular to a propagation of the filtered light beams with the spatially separated regions displaced in the two dimensions along the plane and wherein the broadband light detector receives light in the two dimensions over the plane at independent light sensors displaced in the two dimensions each light sensor associated with only one of the spatially separated regions; and wherein the frequency filter provides more than two layers separated perpendicularly to the two dimensions with adjacent layers having different refractive indices.