The beginnings of the laser age must have been a fun time: crazy new experimental possibilities, beautiful optical demonstrations, dye lasers squirting carcinogens everywhere, and new lasing materials around every corner.
The “edible” laser is a great example:
High-gain directional stimulated emission has been observed for a number of dyes in gelatin with pumping by a nitrogen laser or a liquid dye laser. For some dyes the gel is made with water and gelatin; for others a detergent must be added or glycerin used instead of water. (Source: Hänsch, T.; Pernier, M.; Schawlow, A. IEEE Journal of Quantum Electronics 1971, 7, 45-46.)
I probably would not eat that for multiple reasons: I’m vegetarian, the detergents probably wouldn’t taste good, a nitrogen laser in the eye is unappetizing, and I doubt that fluorescein is food-grade. Theodore Hänsch describes some of these fun laser stories in Optics and Photonics News 2005, 16(2), 14-16 (or the PDF here).
It’s a fun read. Or just read the first page, then look at the pictures, like I did.