The primary and preferred method to ensure safe laser operation. They are comprised of measures designed, engineered and incorporated into a laser or laser system which require minimal to no training for individuals who may be exposed to laser output.

[box]Examples: protective housings, interlocks on removable protective housings, activated shutters, watch-dog timers, etc.[/box]

Electronic modulation of a laser beam to produce high peak power at the initial stage of the pulse. This allows rapid vaporization of the material without heating the surrounding area. Such pulses are many times the peak power of the CW mode.

A measure of the total radiant energy incident on a surface per unit area.  Also Radiant Exposure.

A source of optical radiation with an angular subtense at the cornea larger than α_min. Also, see Point Source.