im Fall Ritzel Haut 632 nm laser Unvergesslich Oswald Halsband
HeNe laser emits light of a wavelength 632.8 nm and has an output power of 2.3 MW. How many photons are emitted each minute by this laser when operated? - Quora
Ring Laser Gyroscope working theory
File:Ring Laser with light inside 632.8 nm.png - Wikimedia Commons