Analytical Description of Tunable Diode Laser Derivative Spectrometry

Abstract
The instrument functions are investigated, and a quantitative description is given of how a second-derivative spectrometer employing a tunable diode laser attains the power to suppress spectral noise. As a result, it is found that the power can be improved by modifying the source-frequency modulation profile. The essence of this approach is to make the profile at its extreme as sharp as possible, and a hyperbolic sine profile with suitable parameters is proposed as the optimal profile that can be attained in practice.