The tendency of some lasers to emit spikes of Output Power particularly after being switched on.
When the pump power of a Laser is suddenly switched on the laser output power may exhibit several spikes, energetic pulses, before it approaches its steady-state value via relaxation oscillations. Similar effects occur when the Resonator losses are suddenly reduced after some time where the Gain medium was pumped. The duration of the first spike can be a few times the resonator round-trip time and is thus often as short as a few tens of nanoseconds. Subsequent spikes then become longer and longer. The repetition Frequency of the spikes is of the SAME order of magnitude as the relaxation oscillation frequency.