Dual-band tunable narrowband near-infrared light trapping control based on a hybrid grating-based Fabry–Perot structure

A hybrid grating-based Fabry-Perot structure is proposed to investigate light manipulation in the near-infrared wavelength region. It is found that the electromagnetic energy can be easily trapped in different parts of the system at different polarization states. For TM polarization, numerical results show that two remarkable narrowband absorptance peaks appear owing to the excitation of critical coupling with guided mode resonance and Fabry-Perot resonance. While for TE polarization, only one narrowband absorptance peak is generated because only Fabry-Perot resonance is excited. The near-infrared spectral selectivity of the system can be tuned by changing the geometrical parameters. In addition, the spectral absorptance of the system can be optimized by applying gate voltage on graphene sheet to change graphene chemical potential. This valuable dual-band tunable narrowband absorber is a potential application for high-performance optoelectronic devices.