It can be used as a research tool for people working in optics labs and might be useful as a teaching aid for an undergraduate-level entry course in modern optics. See notes below You require the latest version of Stuffit Expander to decompress it. Send me an email if you want to be informed of new releases. The radius is negative when the beam is focussing, positive when it is expanding.
Displacements are positive when going to the right.
You can use the units you want, as long as you always use the same units. The program initially starts in cm. The radius is the radius of curvature of the wavefront. The Ultimate Reference for anything related to lasers is Siegman's book. No matter how much it costs at your bookstore, it is well worth it if you plan to do any work with lasers.