Fig. 1. Schematic diagram of the FTIR spectrometer based on graphene photodetection and characterization of the photocurrent signal from the graphene photodetector. (a) Schematic illustration of the FTIR optical path structure; (b) Optical microscope image of the graphene device; (c) Photocurrent microscopy images of the graphene device at different wavelengths; (d) Dependence of the photocurrent response intensity of graphene on the excitation light power at wavelengths of 2400 nm and 5000 nm

Fig. 2. Comparison of the spectral test results of the FTIR spectrometer at different scanning distances and scanning speeds. (a) Scanning speed; (b) Scanning distance ( For clarity, an intensity offset of 1 was added between adjacent scanning speeds and scanning distances)

Fig. 3. Spectral accuracy testing of the FTIR spectrometer based on graphene photodetection under excitation at different wavelengths. (a) Time-domain interferogram of 2200 nm; (b) Time-domain interferogram of 2300 nm; (c) Time-domain interferogram of 2500 nm; (d) Frequency-domain spectrum of 2200 nm; (e) Frequency-domain spectrum of 2300 nm; (f) Frequency-domain spectrum of 2500 nm

Fig. 4. PDMS FTIR characterization results. (a) FTIR spectrum; (b) Absorption spectrum