Fig. 1. (a) System block diagram of our proposed device, and (b) the overall structure of tunable metamaterial-based detector.

Fig. 2. A graphene monolayer-based FET.

Fig. 3. Fermi energies tuning with different gate-source voltages.

Fig. 4. Tunable metamaterial based on Au coaxial squares integrated on monolayer graphene. (a) The overall metamaterial structures. (b) Top view of the metamaterial structures. (c) The simulation unit.

Fig. 5. (a)–(h) Eight different absorption spectra from four tunable metamaterial-based detectors with swept Fermi energies from 0 to 0.3 eV. (i) The overall absorption spectra in one figure plot.

Fig. 6. Reconstructed Gaussian spectra results for the single Gaussian peak with FWHM of 100 GHz in (a), a two-peak spectrum in (b), and random wide spectra in (c) using eight spectra from four tunable metamaterial-based detectors in Fig. 5; (d) the average MSEs of all the reconstructed spectra between ground truths and experimental results in the training data set and testing data set are shown in a red line and a black dashed line.