When you polarize a laser beam, then polarize it again with a second polarizer - perpendicular to the first - no light comes through, right? But when you put a third polarizer in the lineup and adjust the angle, the beam reappears. Why is this? What makes it come back?
IR - Where exactly is it spewing out to? Is it just within the beam or does it diffuse out into open air? What I'm wondering is if standing near a beam or near the source can cause IR damage without taking a shot to the eye.
I have done some searching and don't mean to post about something if...