Continuous Wave (CW) The output of a laser that is operated in a continuous (pulse duration >0.25s) rather than a pulsed mode
Irradiance the amount of power per unit area
Joule (J) the basic unit of energy
LASER Light Amplification by Stimulated Emission of Radiation
Maximum Permissible Exposure (MPE) The level of laser radiation to which a person may be exposed without hazardous effect or adverse biological changes in the eye or skin
Military Exempt Lasers Military lasers exempted under 76EL-01DoD from CFR, Title 21, Chapter I, Subchapter J, Part 1040 where compliance would hinder mission fulfillment during actual combat or combat training operations or when the laser product is classified in the interest of national security. These lasers must comply with MIL-STD-1425A Safety Design Requirements for Military Lasers and Associated Support Equipment
Nominal Hazard Zone (NHZ) The nominal hazard zone describes the space within which the level of the direct, reflected or scattered radiation during operation exceeds the applicable MPE. Exposure levels beyond the boundary of the NHZ are below the applicable MPE
Nominal Ocular Hazard Distance (NOHD) The distance along the axis of the unobstructed beam from the laser to the human eye beyond which the irradiance or radiant exposure during normal operation is not expected to exceed the appropriate MPE
Pulse Duration The duration of a laser pulse; usually measured as the time interval between the half-power points on the leading and trailing edges of the pulse
Pulsed Laser A laser that delivers its energy in the form of a single pulse or a train of pulses (pulse duration <0.25s)
Radiant energy energy emitted, transferred, or received in the form of radiation
Radiant Exposure surface density of the radiant energy received
Watt (W) the basic unit of power (J/s)
Wavelength The distance between two successive points on a periodic wave that have the same phase