Graphene Tunable Plasmon–Phonon Coupling in Mid‐IR Complementary Metamaterial

Abstract

concentration monitoring. [1] In order to improve sensing accuracy, the engineered photon-electron oscillation resonant along the interface or confined in the subwavelength metamaterial can be utilized. [2] This collective electromagnetic oscillating behavior known as plasmonic resonance is able to express the unique optical features under different conditions. Among the various types of plasmonic resonances, Fano resonance is characterized by the sharp asymmetric line shape, created by the interference of a narrow discrete state (black or subradiant mode) with the broadband continuum state (bright or super-radiant mode) and is favorable for constructing slow light or nonlinear optical platform to launch the high-Q enhanced applications, such as biochemical sensing. [3][4][5][6] The most popular approach to the excitation of Fano resonance in the mid-infrared frequency range is to break the symmetry of metamaterial geometry. [7][8][9] There are other methods including the multistacking of thin metal and dielectric layers [10] and making use of material intrinsic damping as the subradiant mode. [11][12][13] For example, with the mid-infrared vibrational absorption resonance (phonon band) of silicon dioxide as the dark mode, the strong Fano coupling between the SiO 2 thin film and metamaterial split ring resonator (SRR) is observed such that it leads to mode splitting featured as frequency anticrossing. [13] In the asymmetric SRR metamaterial, polymethyl-methacrylate (PMMA) produced Fano resonance is enhanced as well. [14] The Fano resonance from metamaterial plasmon coupled with the phonon vibration of PMMA is varied through changing metamaterial geometry. [11,15] Moreover, the realization of the ultrasensitive detection of polymer molecule is obtained through matching the polymer phonon resonance with the Fano resonance of periodic nanostructures. [16] The alteration of Fano resonance can be achieved by the individual or simultaneous control of dark and bright resonance. The aforementioned geometry variation of subwavelength metamaterial can be used to shift the broad bright mode resonance. The alternative approaches such as mechanical stress, [17] liquid crystal, [18] micro electromechanical system technology [19] are exploited to either modify the optical properties of the surrounding material or actively reconfigure the structure. Recently, the dynamic manipulation of Fano resonance by graphene electrostatic tuning has been demonstrated by some groups. [20,21] Metamaterial-based plasmonics has become an overwhelming research field due to its enormous potential and versatility in molecular sensing, imaging, and nonlinear optics. This work presents a new tunable plasmonic platform on which the metamaterial resonance is coupled with infrared vibrational bond in the presence of graphene electrostatic modulation. The maximum electric field enhancement factor induced by mode coupling is 14 and the quality factor (Q-factor) of phonon mode is increased approximately by fourfold. The graphene electrostatic modulation b...

Progress of infrared guided-wave nanophotonic sensors and devices

“…When the sensing area increases by 14.5 times, an over 9% increase in absorption was reported [180]. On top of sensing, low dimensional materials such as graphene have been introduced into the nanoplamonic systems for enhancing plasmonic absorbers [181], enhancing nonlinear optical effects [182], tuning plasmon-phonon coupling [183], and enabling plasmonic modulation [184]. Similar technologies can be utilized in guided-wave nanophotonic biochemical sensors by integrating nanoplasmonics on the sensing waveguide and concentrating a high electric field locally in nanoscale to enhance the sensing performance as well as other applications that require strong light-matter interactions.…”

Recent Progress in Active Optical Metasurfaces

“…Beyond spectrum modulation, more recent studies on graphene‐hybrid metasurfaces have been focused on the advancement of more sophisticated functionalities . The gate‐tunable resonances observed imply that graphene‐loaded metasurfaces may be used for comprehensive manipulation of both amplitude and phase properties of light waves.…”

Leveraging of MEMS Technologies for Optical Metamaterials Applications

“…In recent years, metamaterials with artificially engineered sub‐wavelength structure have shown great advancement in numerous interesting electromagnetic (EM) properties such as artificial magnetism, negative refractive index, metalenses, wavelength selective absorption, slow light behavior, and chirality . To actively control the metamaterial, various efforts have been developed such as the optically pumped photoconductive materials, electrically controlled refractive index of liquid crystals, biasing of doped semiconductor devices or graphene, thermally controlled refractive index of materials, conductivity control in phase change materials, magnetically controlled active materials, and so on . However, the intrinsic frequency‐dependent property of these materials hinders the spectral scalability.…”