Lab talk for a laser holding its intended state: a mode-locked oscillator producing clean pulses, or a single-frequency laser kept on a cavity or atomic line by a feedback servo. Lasers gain lock, hold lock and lose lock, and a log of lock drops is a standard health check. Losing lock in the middle of a measurement can ruin a whole data set.
Oscillator lost lock twice during the night run, both times right when the building HVAC kicked on.
Related terms
Mode locking
Fixing the phases of many longitudinal modes so they add up into a train of ultrashort pulses.
Kick
To start a Kerr-lens mode-locked laser by briefly disturbing the cavity so a pulse can form.
Linewidth
The spectral width of a single-frequency laser's output, usually given in Hz, kHz or MHz at half maximum.
CW breakthrough
A narrow continuous-wave spike in a mode-locked laser's spectrum, showing part of the power is not pulsing.