Far-Field Imaging

An imaging technique with solid-state lasers that has several limitations: non-uniform energy distribution, very short working distances, and poor control of hole geometry.

Flashlamp

Source of powerful light; often in the form of a helical coil and used to excite photon emission in a solid-state laser.

Flexography

A printing process involving laser-engraved, seamless rubber plates.

Focal Length

The distance from the secondary nodal point of a lens to the secondary focal point. For a thin lens imaging a distant source, the focal length is the distance between the lens and the focal point.

Focal Point

Also Focus (noun).  The point toward which radiation converges or from which radiation diverges or appears to diverge.

Folded Resonator

Construction in which the interior optical path is bent by mirrors mounted on corner blocks bolted into pre-aligned position, permitting compact packaging of a long laser cavity.

Frequency

The number of light waves passing a fixed point unit of time, or the number of complete vibrations in that period of time.