Dual comb spectroscopy for web thickness measurement

Abstract

The present disclosure provides a method comprising generating, by a dual frequency comb source, a first optical frequency comb having a first repetition rate and a second optical frequency comb having a second repetition rate that is different from the first repetition rate. The method includes directing, using one or more optical elements, one or more of the first optical frequency comb or the second optical frequency comb toward a material. The method includes detecting, using a diode photodetector, optical signals from the first optical frequency comb and the second optical frequency comb after interaction of one or more of the first optical frequency comb or the second optical frequency comb with the material. The method includes generating, using the diode photodetector, a radio frequency signal corresponding to the optical signals. The method includes determining a thickness of the material based on the radio frequency signal.

Dependencies are inferred from the claim text.