Fun fact! The Laser in the burner didn't actually burn from thermal effects, and instead caused a chemical reaction using specific wavelengths of light to activate a substrate called pthalocyanine.
This is part of why you could burn "faster", although typically you had a higher quality burn at slower speeds as the change from one color to another via the chemical effects was more complete. This allowed weaker reading lenses to better perceive the new colors easier, and greatly increased compatibility.
I am very, very old.