Abbreviated MPE.  The level of laser radiation to which an unprotected person may be exposed without adverse biological changes to the eye or skin.

The lens used primarily in CO2 lasers by Coherent, Inc. It has one side convex, the other concave.

Unstable condition in which the energy of a molecule is at some discrete level above the lowest, or ground state. It is this condition which is necessary for emission of photons in a laser. (From quantum theory.)

A “MY-kro’ mee-ter” is a unit of length equal to one millionth of a meter, or one micron. (Not to be confused with my-KROM’-a-ter, a measuring instrument used with a telescope, microscope, or laser for fine focusing).

One thousandth of a Joule.