reZonator is a powerful software for designing laser resonators and calculation the propagation of light beams (as gaussian so as ray vectors) in complex optical systems. It has a modern, user-friendly interface, so you need no specialized training or programming skills to use all of its functions and tools.
You can use the program for educational purposes. Still, it was created as a real working tool for computer modeling of laser cavities and currently used in many research organizations over the world.

NOTE: This is only to provide appimages, I am not the developer.