The amount of radiant energy available per unit; the radiant flux.

Part of the energy in a photon is transferred to (or from) the vibrational/rotational energy of a molecule.

Power controls for accomplishing the ramping steps; may be computer-controlled.

The ratio of the reflected flux to the incident flux, or the ratio of reflected light to light falling on the object.

The return of radiant energy (incident light) by a surface, with no change in wavelength.