Role of grating parameters on the excitation of plasmon–polaritons in graphene

Abstract In this paper, the effect of grating parameters on the excitation of plasmon–polaritons in a graphene layer placed on a rectangular grating is investigated. By solving the electromagnetic wave equation inside the device structure, the transmittance spectra of the device and the absorbance spectra of the graphene layer are calculated by varying the structure parameters. The results show that with the decrease of the Fermi energy level in the graphene layer, plasmon–polaritons are excited at longer wavelengths. With the increase of the grating ridge height, the absorbance at peak spectra points increases, and then saturates. The start of the saturation point depends on the grating ridge material. The results indicate that the best value for the grating ridge height is 0.7 or 0.4 times the grating period when the grating ridge material is doped silicon or gold, respectively. Duty cycle affects the efficiency of plasmon–polariton excitation, where the best values for the duty cycle are 0.75 or 0.65 when the grating ridge material is doped silicon or gold, respectively. With the choice of these best values one can excite plasmon–polaritons in the graphene layer more efficiently, which is useful for sensing and photodetection applications.