Hi. Thanks for having this great site. The applets are a big help in my lectures. I noticed the optics applets are mostly from geometric optics. (ray tracing, thin lenses, reflection/refraction, etc.) It would be nice also if you have applets that demonstrate some topics from physical optics. (light interference, Fraunhofer and Fresnel diffraction through various apertures or obstacles, polarization, etc.) Thanks again and best regards