Diode laser spectrometer for high-precision measurements

The issues of the development, calibration and putting into operation of a diode laser spectrometer for high-precision measurements are considered. The tests rely on the use of an isolated P20 line of the 00031–00001 band of the ¹²C¹⁶O₂ molecule. The spectrometer error budget is analysed. A software programme for the approximation of a spectral line contour is designed and the procedure is analysed. It is shown that, for a baseline with a relative level of 2.3 × 10^-5, it is optimal to use no more than six fitting parameters in the line contour approximation. The measured integral intensity of the analytical line constitutes 5.3865(85) × 10^-23 cm per molecule.