PulseIntermittent Emission of laser beam.
Pulsed: A pulsed laser delivers laser beams in pulses. Instead of lasing your skin in one continuous beam, pulsed lasers zap your skin in beats. Therefore, instead of going zaaaaaaap like a continuous wave laser, pulsed lasers go zap, zap, zap. There are long-pulsed pulsed lasers, with a pulse duration of around 30-50 milliseconds, and short-pulsed pulsed lasers, with a pulse duration of around 5-100 nanoseconds.
A condition of matter in which more electrons are in a higher energy state than in a lower energy state, as is required for the operation of a laser.
For an atomic system, the condition where there are more electrons in a higher energy state than a given lower state, such as the ground state. Population inversion is required to establish and maintain lasing action. Since atomic systems tend to prefer more electrons in lower states, external energy, such as electromagnetic radiation of a suitable frequency, is required to maintain population inversion.