Fig. 1. Principle of remote sensing detection for greenhouse gases

Fig. 2. Spectral radiance of each channel. (a) Channel 1 with 405‒490 nm; (b) channel 2 with 747‒773 nm; (c) channel 3 with 1590‒1675 nm; (d) channel 4 with 1990‒2095 nm; (e) channel 5 with 2325‒2385 nm

Fig. 3. Structural design scheme of greenhouse gas imaging spectrometer

Fig. 4. Pupil vector transformation between off-axis system and coaxial system

Fig. 5. Schematic diagram of the multi-component coated prism color separation technology

Fig. 6. Three-dimensional layout of the telescopic system

Fig. 7. MTF of the telescopic system

Fig. 8. Spot diagrams of the telescopic system

Fig. 9. Two-dimensional diagram of the collimation system

Fig. 10. Two-dimensional diagrams of the dispersion system for different channels. (a) Channel 1 with 405‒490 nm; (b) channel 2 with 747‒773 nm; (c) channel 3 with 1590‒1675 nm; (d) channel 4 with 1990‒2095 nm; (e) channel 5 with 2325‒2385 nm

Fig. 11. Schematic diagram of the orthogonal combined prism color separation system

Fig. 12. Physical diagram of the spectrometer system

Fig. 13. Comparative analysis of ghost images in channel 1 of the spectrometer. (a) Normal imaging; (b) non-working band imaging

Fig. 14. MTF curves of each channel for the imaging spectrometer. (a) 447.5 nm; (b) 760 nm; (c) 1632.5 nm; (d) 2042.5 nm;

Fig. 15. Spot diagrams of each channel for the imaging spectrometer. (a) Channel 1 with 405.55‒406.65 nm; (b) channel 2 with 747.00‒747.22 nm; (c) channel 3 with 1632.27‒1632.73 nm; (d) channel 4 with 2042.20‒2042.80 nm; (e) channel 5 with 2354.75‒2355.25 nm