Incident Light

A unit of measurement for a wavelength of light (written Å), equal to one ten billionth of a meter (10^-10 meter).  (Used occasionally.)

All undesirable variations in output (either amplitude or frequency); angular drift of the beam, measured in milliradians before, during, and after warm-up.

An electrical element in laser excitation which attracts electrons from a cathode. An anode can be cooled directly by water or by radiation.