Spectrometer Optical Design

Performing stray light analysis on remote-sensing hyperspectral instruments at Ball Aerospace provided me with a good introduction to spectrometer design forms. I used non-sequential raytracing to look for potential design issues related to gratings, prisms, and spectral filters, as well as scatter from surface roughness/contamination and ghosts between optical surfaces. I learned about keystone and smile from the optical designers and the impacts of spectral cross-contamination from the systems engineers.

Since then, I’ve designed a few spectrometers myself. I worked with a university professor on the design of an astronomical spectrometer and more recently, designed two compact freeform spectrometers for an aerospace client.

I designed the Offner spectrometer example below for a spectral range of 400-1000 nm.