gas laser A gas laser is a laser in which the lasing medium is a gas. The laser medium is places between two parallel mirrors for light emission amplification. The gas is excited to emit light via an external light source or an electric current discharging through the gas. Daniel Schober John Quinn gas laser helium-neon gas laser used to erradiate cells in a flow cytometer. http://en.wikipedia.org/wiki/Gas_laser laser metadata incomplete