LAMBERTIAN SURFACE An ideal diffuse surface whose emitted or reflected radiance
(brightness) is dependent on the viewing angle.
LASER An acronym for light amplification by stimulated emission of radiation.
A laser is a cavity, with mirrors at the ends, filled with material such as crystal,
glass, liquid, gas or dye. A device which produces an intense beam of light with
the unique properties of coherency, collimation and monochromaticity.
LASER ACCESSORIES The hardware and options available for lasers, such as secondary
gases, Brewster windows, Q-switches and electronic shutters.
LASER CONTROLLED AREA See CONTROLLED AREA.
LASER DEVICE Either a laser or a laser system.
LASER MEDIUM (Active Medium) material used to emit the laser light and for
which the laser is named.
LASER OSCILLATION The buildup of the coherent wave between laser cavity end
mirrors producing standing waves.
LASER PRODUCT A legal term in the U.S. See 21 CFR 1040.10, a laser or laser
system or any other product that incorporates or is intended to incorporate a
laser or a laser system.
LASER ROD A solid-state, rod-shaped lasing medium in which ion excitation is
caused by a source of intense light, such as a flashlamp. Various materials are
used for the rod, the earliest of which was synthetic ruby crystal.
LASER SAFETY OFFICER (LSO) One who has authority to monitor and enforce measure
to the control of laser hazards and effect the knowledgeable evaluation and control
of laser hazards.
LASER SYSTEM An assembly of electrical, mechanical and optical components which
includes a laser. Under the Federal Standard, a laser in combination with its
power supply (energy source).
LEADING EDGE SPIKE The initial pulse in a series of pulsed laser emissions,
often useful in starting a reaction at the target surface. The trailing edge of
the laser power is used to maintain the reaction after the initial burst of energy.
LENS A curved piece of optically transparent material which depending on its
shape is used to either converge or diverge light.
LIGHT The range of electromagnetic radiation frequencies detected by the eye,
or the wavelength range from about 400 to 760 nanometers. The term is sometimes
used loosely to include radiation beyond visible limits.
LIGHT REGULATION A form of power regulation in which output power is monitored
and maintained at a constant level by controlling discharge current.
LIMITING ANGULAR SUBTENSE The apparent visual angle which divides intrabeam
viewing from extended-source viewing.
LIMITING APERTURE The maximum circular area over which radiance and radiant
exposure can be averaged when determining safety hazards.
LIMITING EXPOSURE DURATION An exposure duration which is specifically limited
by the design or intended use(s).
LONGITUDINAL OR AXIAL MODE Determines the wavelength bandwidth produced by
a given laser system controlled by the distance between the two mirrors of the
laser cavity. Individual longitudinal mode standing waves within a laser cavity.
LOSSY MEDIUM A medium which absorbs or scatters radiation passing through it.