Optimization of operating modes of the weak absorption spectrometer

Abstract

The possibilities of improving the characteristics of a weak absorption spectrometer consisting of a frequency-tunable laser and an external analytical resonator with the test substance are analyzed. The influence of the scanning speed of the laser frequency on the choice of the spectrometer operating modes that provide the required resolution and the required sensitivity of spectral measurements is considered. Particular attention is paid to assessing the role of the interaction of modes in an analytical cavity on the structure of the recorded spectra. It was found that at a high rate of change in the laser frequency and superposition of fields of longitudinal modes, an improvement in the resolving power is combined with a certain decrease in the sensitivity and accuracy of recording weak spectral lines. It is shown that the optimization of the spectrometer operation modes requires correct accounting of the Q-factor of the analytical resonator and the line width of the probe radiation.