The amount of visible light usable to the eye that passes through a filter. As a rule of thumb, as optical density increases, visible light transmission decreases — but not always. Also (same as) Visible Light Transmission.

Abbreviated TEM. The cross-sectional shape of the working laser beam. An infinite number of shapes can be produced, but only a relatively small number are needed for industrial applications. In general, the higher the TEM, the coarser the focusing.

Relative motion of the beam with respect to the part, usually in a circular fashion. See Rotating Lens.

The loss of light through an optical element when the entire bundle does not pass through; an image or picture that shades off gradually into the background.

The amount of visible light usable to the eye that passes through a filter. As a rule of thumb, as optical density increases, visible light transmission decreases — but not always. Also (same as) Transmittance.