Tunable Group Delay of the Optical Pulse Reflection From Fabry–Perot Cavity With the Insertion of Graphene Sheets

Abstract

We have theoretically investigated the group delay of the TE-polarized beam reflected from a Fabry-Perot cavity with the insertion of the graphene sheets in the nearinfrared band. It is shown that even a single-layer graphene allows for notable variation of group delay. Group delay can be enlarged negatively and can be switched from positive to negative, or vice versa. Importantly, the group delay depends on the Fermi energy of the graphene sheets, and thus, it can be actively controlled through electrical or chemical modification of the charge carrier density of the graphene. Furthermore, the influences of the position of graphene in the Fabry-Perot cavity, the mirror transmittance, and the number of graphene layers on group delay are clarified.

Tunable positive and negative group delays of light reflection from layer structures with a graphene layer

“…considered as a zero-thickness layer characterized by the two dimensional conductivity [33,[39][40][41][42]. On the other hand, it can be seen as a thin layer with effective dielectric constant [47,48].…”

“…Li et al investigated the graphene ribbon waveguide and achieved an outstanding plasmonically induced transparency window with a group time up to 0.28ps [38]. On the other hand, in 2014 [39], Jiang et al investigated the negative group delay of the TEpolarized beam reflected from a Fabry-Perot cavity with the insertion of the graphene. Next year, they found that a fast pulse reflection can take place from the graphene covered lossless dielectric slab [40].…”

Enhanced and tunable transmitted group delays based on epsilon-near-zero response of Weyl semimetal

“…7 In this situation, various mechanisms and structures have been proposed to enhance and control the group delay. For instance, the enhanced reflected and transmitted group delays in structures, such as the electromagnetically induced transparency system, 8 Fabry-Perot cavity structure, 9 weakly absorbing dielectric, 10 and metamaterial, 11 have attracted interests. In terms of experiments, Longhi et al 12 proposed a double Lorentzian fiber Bragg grating to observe the reflected group delay of optical pulses.…”

Enhanced Group Delay of the Pulse Reflection with Graphene Surface Plasmon via Modified Otto Configuration

“…The potential applications of the above group delay properties include controllable all-optical delays [3], arbitraryangle beamforming [4], and all-optical buffers [5]. Various techniques and approaches have been explored to accomplish the tunable and large group delay in order to achieve the extraordinary phenomena described as "subluminal effect" and "superluminal effect" in various frequency ranges, like electromagnetically induced transparency (EIT) systems [6], weakly absorbing dielectric [7], Fabry-Perot cavity configuration [8], metamaterial slab [9], and so on. Compared with the subluminality, the superluminality characterized by negative group delay continues to attract much attention due to the counterintuitive phenomenon and the possible applications.…”