Laser-based spectroscopic detection techniques

摘要

One embodiment of the present invention includes: a modulated laser light source to transmit an interrogation light beam to a region including a substance for spectroscopic evaluation, a detector responsive to modulated light from the region to provide a corresponding modulated signal, and a signal processing subsystem responsive to the modulated signal to generate a spectroscopic absorption peak representation. This subsystem also estimates absorbance based on a derivative form of an absorption peak and a residual amplitude modulation level corresponding to the absorption peak.