A four-band coherent perfect absorber in the near-infrared region based on borophene metamaterial

We propose a coherent perfect absorber based on a borophene metamaterial grating structure. Based on the theoretical analysis of the temporal coupled mode theory and the numerical results of the finite-difference time-domain simulations, the transmission characteristics of the system are investigated. The dynamic tunability of the absorption intensity and resonance wavelength is realized by adjusting the phase difference and carrier density of the coherent incident beams. Moreover, by tuning the parameters, the coherent perfect absorption peak (99.99%) is obtained near the wavelength of 1550 nm, that is, the third communication window. Meanwhile, the structure can operate in ultra-thin gratings as low as 6 nm and angle tolerances as large as 45°, which provides the possibility for applications in highly integrated and wide-angle devices.