Fig. 1. Schematic of near infrared laser C2H2 sensor system based on OLIA and SFFT

Fig. 2. Flow charts of extracting 2f signal based on (a) OLIA and (b) SFFT

Fig. 3. (a) Simulated absorption signal as well as output 2f signals from (b) OLIA and (c) SFFT with C2H2 volume fraction of 10-4

Fig. 4. Photograph of near-infrared laser C2H2 sensor system

Fig. 5. C2H2 sensor calibration results obtained by (a) OLIA and (b) SFFT

Fig. 6. Fitting curves of 2f amplitude versus C2H2 concentration. (a) OLIA; (b) SFFT

Fig. 7. Allan deviation curves of near-infrared C2H2 sensor system. (a) OLIA; (b) SFFT