Patent ID: 11604096

Abstract:
A spectral imager (100) may use an entrance telescope (10) to spatially image an object (O1), at least in the across-slit direction (X), onto a physical slit (Se) of a spectrometer (20). The spectrometer (20) may include a slit homogenizer (24) such as a rod lens configured to spatially image an aperture stop (AS) in the across-slit direction (X) as a virtual slit image (Ih). Formation of a detection image (Id) which is spectrally resolved along a spectral axis (X′) may includes spatially imaging the virtual slit image (Ih), at least in the across-slit direction (X), at a detector plane (Pd). This may achieve a more homogeneous illumination of the spectrometer slit and improve measurement accuracy and reproducibility.