(Untitled)

Colorful flames and smoke?

This is actually Newton’s Rings again, a colorful microscopic pattern that appeared on my sample of laser material after some isopropyl alcohol dried funny.  It must have left a thin film of something behind, and that produced rainbow patterns in the same way a thin soap bubble film does.  The rainbow patterns are just barely visible by eye, but under a microscope (like this), you can see all sorts of detail.

Fortunately, the fix was simple: another isopropyl alcohol rinse, followed by a more careful dry.  Rainbow patterns gone - on with science!