Fig. 1. Laser transitions of CO₂ isotopes at bands 00⁰1-10⁰0 and 00⁰1-02⁰0

Fig. 2. Output characteristics under different atom ratios, where the left images show the input and output pulse waveforms and the right images show the output spectra and amplifier gain spectra. (a)(b) ¹³C and ¹⁸O account for 0%, respectively; (c)(d) ¹³C and ¹⁸O account for 25%, respectively; (e)(f) ¹³C and ¹⁸O account for 50%, respectively; (g)(h) ¹³C and ¹⁸O account for 75%, respectively; (i)(j) ¹³C and ¹⁸O account for 100%, respectively

Fig. 3. Output characteristics in four bands with ¹⁸O accounting for 50%, where the left images are the input/output pulse waveforms and the right images are the output spectra and amplifier gain spectra. (a)(b) 10.532 μm; (c)(d) 10.247 μm; (e)(f) 9.411 μm; (g)(h) 9.222 μm

Fig. 4. Output characteristics under the conditions of different pressures and CO₂ isotopes (¹²C¹⁶O₂ and the gas with six CO₂ isotopes with ¹³C and ¹⁸O accounting for 50%, respectively) at 5, 8 and 10 bar, where the left images are the input/output pulse waveforms and the right images are the output spectra and amplifier gain spectra. (a)(b) At 5 bar, the proportions of ¹³C and ¹⁸O are 0%, respectively; (c)(d) at 5 bar, the proportions of ¹³C and ¹⁸O are 50%, respectively; (e)(f) at 8 bar, the proportions of ¹³C and ¹⁸O are 0%, respectively; (g)(h) at 8 bar, the proportions of ¹³C and ¹⁸O are 50%, respectively; (i)(j) at 10 bar, the proportions of ¹³C and ¹⁸O are 0%, respectively; (k)(l) at 10 bar, the proportions of ¹³C and ¹⁸O are 50%, respectively

Fig. 5. Gain near 10.591 μm at 10 bar and gain contribution of each isotope

Fig. 6. Amplifier gain spectra at 8.8-11.7 μm band. (a) ¹³C accounts for 0% and ¹⁸O accounts for 50%; (b) ¹³C accounts for 100% and ¹⁸O accounts for 50%; (c) ¹³C accounts for 50% and ¹⁸O accounts for 50%

Fig. 7. Output characteristics at 9 and 10 μm band under different CO₂ isotopes (three isotopes of ¹²C, three isotopes of ¹³C and all six isotopes), where the left images are the input/output pulse waveforms and the right images are the input/output spectra and amplifier gain spectra. (a)(b) 9.330 μm, ¹³C accounts for 0% and ¹⁸O accounts for 50%; (c)(d) 9.442 μm, ¹³C accounts for 50% and ¹⁸O accounts for 50%; (e)(f) 10.869 μm, ¹³C accounts for 100% and ¹⁸O accounts for 50%; (g)(h) 10.767 μm, ¹³C accounts for 50% and ¹⁸O accounts for 50%