Fig. 1. Structural diagram of experimental system for gas absorption spectrum measurement

Fig. 2. Interference signal and laser transmission signal of etalon. (a) Interference signal; (b) laser transmission signal

Fig. 3. Experimental result, nonlinear least square fitting result, and fitting residual. (a) Experimental result and nonlinear least square fitting result; b) fitting residual

Fig. 4. Linear fitting results of absorbance lines at 6807.83 cm^-1 and 6808.04 cm^-1 under different pressures, and line strength curve measured by experiment and database theory line strength curve. (a) Linear fitting results of absorbance line at 6807.83 cm^-1 under different pressures; (b) linear fitting results of absorbance line at 6808.04 cm^-1 under different pressures; (c) line strength curve measured by experiment and database theory line strength curve

Fig. 5. Collisional broadening values and linear fitting results of absorption lines at 6807.83 cm^-1 and 6808.04 cm^-1 under different pressures, and self-broadening FWHM coefficients and optimal fitting results of absorption lines at 6807.83 cm^-1 and 6808.04 cm^-1 under different temperatures. (a) Collisional broadening values and linear fitting results of 6807.83 cm^-1 absorption line at different pressures; (b) collisional broadening values and line