Patent ID: 7321425

Claim:
A sensor, for measuring at least one component in a composition, that comprises: a broadband light source that generates light; an acousto-optic tunable filter (AOTF); optics that direct a beam of light at the AOTF, wherein the AOTF is tuned to pass detection light having a desired wavelength range to detect a concentration of the at least one component in the composition; a screen that directs the detection light of known wavelength to the composition; a detector that receives light that emerges from the composition; and a control signal generator that provides the AOTF with at least one desired wavelength range that is characteristic of the least one component in the composition; wherein the composition comprises paper, and wherein the sensor detects at least one of: a level of cellulose in the paper, a level of calcium carbonate in the paper or paper coating, a level of clay in the paper or paper coating, and a level of latex in the paper or paper coating.