Hyperspectral push-broom imager using a volume Bragg grating as an angular filter

Abstract

A hyperspectral push-broom imager has been designed, constructed, and tested. The narrow angular selectivity of a weakly index modulated volume Bragg grating is utilized to replace the objective lens, slit, and collimating lens of a conventional slit-based hyperspectral push-broom imager. The imager comprises a dispersion grating, an angular filter grating, a focusing lens, and an image sensor. The imager has a field of view (FOV) of 17 degrees in the spatial direction, a spectral range from 400 nm to 900 nm, and a spectral resolution of 2.1 nm. The acquired hyperspectral data cubes are presented, and the influence of wavelength-dependent incident angle errors is analyzed.