2015-05-042015-05-042011-08-30Kosterev, Anatoliy A. and Curl, Robert F., "Modulation cancellation method in laser spectroscopy." Patent US8009293B2. issued 2011-08-30. Retrieved from https://hdl.handle.net/1911/80066.https://hdl.handle.net/1911/80066Novel methods and laser spectroscopic systems for accurately measuring the concentration of compounds are disclosed herein. The disclosed methods utilize a modulation cancellation technique resulting in a significantly increase in the sensitivity and accuracy of laser spectroscopic measurements. In general, the methods and systems utilize modulation phase-shifting and amplitude attenuation to cancel the signals detected from at least two modulated light beams. Thus, any signal detected will be directly proportional to the concentration measurement.9 ppengUtility patentUS8009293B2