Assembly and alignment method for optimized spatial resolution of off-axis three-mirror fore optics of hyperspectral imager.

A fore optics for the hyperspectral spectrometer is designed, manufactured, assembled, and aligned. The optics has a telecentric off-axis three-mirror configuration with a field of view wider than 14 degrees and an f-number as small as 2.3.

Efficient method to measure the spectral distortions using periodically distributed slit in hyperspectral imager.

The imaging spectrometer generally shows geometrical asymmetric distortions known as the keystone and smile that are different from the regular imaging optical system. The conventional method of measuring such distortions requires a precision movement control stage and specialized optical setup. Moreover, it is even harder to measure other characteristics such as the wave front error (WFE) simultaneously and to repeat the measurements since an accumulated vast number of statistical data is required to calculate the keystone and smile.