Question: Can there be different colours of lazers so things that burn can burn in bright colours? :))

Jesse Dykes answered on 9 Mar 2020:

There can, the colour of a laser depends on the material you put inside. The first lasers used ruby crystal, which gives a red laser. Some have gases inside like Helium and Neon, or CO2, which give red and green. Recently we’ve got semiconductor lasers which can be blue. If you used all of them at once you could make all sorts of colours, the same as how if you look really closely at a screen you’ll little red green and blue rectangles which make up different colours