Any device(s) employed to partially (e.g., laser attenuative translucent window materials) or fully (e.g., opaque curtains) diminish or restrict the transmission of incipient laser light.

Hardware assembly or optical device, such as a mirror, capable of changing laser beam direction; used to re-point the beam and in folded, compact delivery systems.

The diameter of that portion of the beam which contains 86% of the output power.

The increase in the diameter of the laser beam with distance from the exit aperture, based on the full angle at the point where the irradiance (or radiant exposure for pulsed lasers) is 1/e times the maximum value. Symbol: Ф

Optical device increasing beam diameter and reducing divergence. Result: A smaller focused spot for more distance between lens and part.