The energy per second emitted from the laser in the form of coherent light, usually measured in watts for continuous-wave operation and joules for pulsed operation.

In certain cutting operations, coaxial oxygen initiates an exothermic reaction to enhance the cutting rate for thick metals; in other words, oxygen actually does the cutting, with the reaction being maintained by the laser beam.

Arises with the use of very short-duration high-energy laser pulses, at pulse durations typically below 10 microseconds. Significant amounts of energy are absorbed and a rapid expansion occurs in the tissue, generating an acoustic shock wave that causes mechanical disruption to cellular structures.

Effects that occur from long exposure durations at incident power levels insufficient to cause damaging photothermal effects. It is an energy dependent process (a function of the total quantity of radiation absorbed rather than its rate of absorption).

An instrument which measures luminous intensity.