Fig. 3
The broadband tuning and sensing performance of EIT resonance under the synchronous voltage tuning scheme. a Applied synchronous bias voltages (V1 = V2) to the U-RCR and D-RCR for manipulating the Fermi level. b, c The broadband tuning transmission spectra of EIT resonance. The black frame marks the scanning range of EIT resonance (0.5 \(\sim\) 2.0 THz). The cyan dotted line marks the sweeping envelope of EIT resonance. d Extracted the local electric field enhancement factors corresponding to the EIT resonance at different Fermi levels. e The perturbation effect of the ultra-thin sample layer (\(\widetilde{n} =\) 1.5 \(+\) 0.2i) with a thickness of 1 μm, and here the EIT resonance corresponds to \({E}_{F1}={E}_{F2}=\) 1.5, 2, 2.5 eV. f The refractive index frequency shift caused by analytes with different thickness, and here the EIT resonance corresponds to \({E}_{F1}={E}_{F2}=\) 2 eV (left panel). The maximum refractive index frequency shift caused by analyte with a thickness of 10 μm, and here the EIT resonance corresponds to different Fermi levels (right panel). And the refractive index of analytes is 2 RIU