Jeff says: My background is in plasma physics, and 20 years of experience is as a jack-of-all-trades. I am a specialist in non-sequential raytracing, and unusual problems which resist standard analysis techniques. These include writing custom DLL add-ons for unusual optical shapes, source functions, or scattering properties -- as well as problems which require a suite of Zemax raytracing plus separate analysis code or raytracing superimposed on 3D solid modeling. I have licenses for SolidWorks and Lahey/Fujitsu Fortran with GINO graphics to complement the capabilities of Zemax.
 

Knowledge Base articles by Jeff Casey:
How to Write User-Defined Sources and Scatter Functions in Fortran
Programming Custom Light Sources and Uniform Deviates