Diode-laser second-derivative modulation spectrometry is a simple means of measuring trace concentrations of small molecules in the gas phase. For a setup with a reference cell used both for laser frequency locking and as a concentration standard, the calibration algorithm is developed for the general case of nonvanishing nonlinear terms in the power expansion of Beer’s law in both the sample and reference channel. A practical example is given.
© 1984 Optical Society of America
Claus Weitkamp, "Calibration of diode-laser second-derivative modulation spectrometry with a reference cell," Appl. Opt. 23, 83-86 (1984)