Q

Q-switch

A device that has the effect of a shutter to control the laser resonator’s ability to oscillate. Control allows one to spoil the resonator’s “Q-factor”, keeping it low to prevent lasing action. When a high level of energy is stored, the laser can emit a very high peak power pulse.

Q-switched laser

A laser that stores energy in the laser media to produce extremely short, high-intensity bursts of energy.

Quantum efficiency (QE)

In an optical source or detector, the ratio of the number of generated photons per second to the number of electrons flowing per second.