Double-pass spectrometer using a flat reflective diffraction grating and multi-element lenses

Abstract

A spectrometer includes an entrance aperture, a lens system that receives and collimates light, a flat reflective diffraction grating that diffracts and reflects the light back through the lens system, and a sensor that detects the returned light. The lens system collimates the light during a first pass and focuses it onto the sensor during a second pass. Various embodiments include selectable entrance apertures, imaging optics, different grating geometries and groove densities, and configurations supporting telecentric performance or multi-channel spectral acquisition.

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