Anomalous redshift of graphene absorption induced by plasmon-cavity competition

Abstract

Anomalous redshift of the absorption peak of graphene in the cavity system is numerically and experimentally demonstrated. It is observed that the absorption peak exhibits a redshift as the Fermi level of graphene increases, which is contrary to the ordinary trend of graphene plasmons. The influencing factors, including the electron mobility of graphene, the cavity length, and the ribbon width, are comprehensively analyzed. Such anomalous redshift can be explained by the competition between the graphene plasmon mode and the optical cavity mode. The study herein could be beneficial for the design of graphene-based plasmonic devices.

Bandwidth tunability of graphene absorption enhancement by hybridization of delocalized surface plasmon polaritons and localized magnetic plasmons

“…This very low and universal (wavelength-independent) absorption efficiency of 2.3% is not beneficial in the aspect of photoelectric devices. To improve the graphene absorption as far as possible, a variety of physical methods are proposed recently, such as different types of surface plasmon resonances [7][8][9][10][11][12][13], critical coupling of guided mode resonances [14][15][16], Fabry-Perot resonances [17][18][19], photonic crystal defect states [20][21][22][23], attenuated total reflections [24][25][26][27], and so on. Through these physical methods, the electromagnetic fields on the graphene surface are enhanced hugely, and thus the graphene absorption is improved greatly [3].…”