Something to keep in mind is that when you bounce light through a high-quality piece of glass, it has less imperfections, and you get less interesting results. At least that is what Dykstra and Apogee found out on LIFEFORCE. They bought a really nice pricey piece of crystal and the laser just went through it without much of anything visual, so that's why they went with the pressed-glass ashtrays! I know they did put a laser through a crystal fairly successfully years earlier for the photon torpedoes in the first TREK movie, but the results look kinda cartoony because they went so many generations that the soft edged flares got all hard-looking. But I guess before they got busy going generations in making the comp that it was supposed to be too cool for school.
I absolutely love low-tech fx. Sometimes I'll dig out the old CINEFEX on THE RIGHT STUFF just to get re-inspired, as they spent months trying to program motion control moves on aircraft models, only to find out they were better off throwing foam models out of upper-floors down at a camera underneath! That, and putting somebody's personal vibrator on the camera to get a bit of turbulent shake, really made the shots live a little.