Hybridization-induced resonances with high-quality factor in a plasmonic chipscale ring-disk nanocavity

Abstract

Plasmonic resonators have drawn more attention due to the ability to confine light into subwavelength scale. However, they always suffer from a low quality (Q) factor owing to the intrinsic loss of metal. Here, we numerically propose a plasmonic resonator with ultra-high Q factor based on plasmonic metalinsulator-metal (MIM) waveguide structures. The resonator consists of a disk cavity surrounded by a concentric ring cavity, possessing an ultra-small volume. Arising from the plasmon hybridization between plasmon modes in the disk and ring cavity, the induced bonding hybridized modes have ultra-narrow full wave at half maximum (FWHM) as well as ultra-high Q factors. The FWHM can be nearly 1 nm and Q factor can be more than 400. Furthermore, such device can act as a refractive index sensor with ultra-high figure of merit (FOM). This work provides a novel approach to design plasmonic high-Q-factor resonators, and has potential on-chip applications such as filters, sensors and nanolasers.

Design and Simulation of a Plasmonic Refractive Index Nano-Sensor Based on Tunable Fano Resonance

“…By comparing their reported sensitivities for resonances, it can be concluded that sensitivities which are located in the visible light region are lower than those which are located in the near infra red region. (Zhang et al 2016), (Zhang et al 2020), (Wang et al 2019) and (Zhang et al 2018) have reported sensitivities of 596 nm/RIU, 579 nm/RIU, 623.8 nm/RIU, and 708 nm/RIU, respectively for their resonances in the visible light region. In order to extract the sensor parameters (S and FOM) for the total system equipped with two triangular silver patches inside the disk cavity (Fig.…”

“…The proposed waveguide system in this work has seven different geometrical parameters (Fig. 1b), which for brevity, the results of optimization for only two of them (x and 𝑔 2 ) was mentioned in subsection 3.3. unlike the simple MIM waveguide (which are applied in (Zhang et al 2018;Zhang et al 2020), with no additional cavity, that has only the geometrical parameter of width (width of insulator between two metal) to be evaluated, in this work, more decisive geometrical parameters on transmission spectra of the total system provided more variables to be applied in the optimization of the FOM of the resonances and resulted in FOM of 598.1 RIU −1 for the resonance of VL2.…”

“…Several studies have demonstrated structures such as the MIM waveguide side coupled with a ring or disk resonator, which could be applied as a refractive index sensor (Wang et al 2019;Zhang et al 2018;Yu et al 2019;Zhang et al 2020). In our previous paper (Moeinimaleki et al 2021) design of a nano-scaled plasmonic waveguide temperature sensor coupled to a rectangular cavity (filled with ethanol) equipped with polygonal metal patches positioned along the cavity has been proposed Which showed the ability of concentrating the fields at its patches' sharp edges in the cavity to enhance the sensing mechanism and resulted in 0.97 nm/°C sensitivity.…”

Double Spectral Electromagnetically Induced Transparency Based on Double-Bar Dielectric Grating and Its Sensor Application

“…In order to make the refractive index change of the dielectric more sensitive, d 2 was set to 3740 nm. The performance of the sensor was evaluated by two factors, sensitivity (S) and FOM [29]:…”

Design and simulation of refractive index sensor based on suspended composite hybrid plasmonic waveguide for sensing mass density of polarizable hydrogen gas

“…3 Therefore, many plasmonic sensors have been investigated and proposed lately. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] In waveguide-based plasmonic refractive index sensors, the sensing mechanism is through the interaction of their supported modes with their surrounding insulator test medium. 13 Unlike dielectric waveguides, where the light is steered through the total internal reflection (TIR) phenomenon, in plasmonic waveguides, electromagnetic waves are guided in the form of surface plasmon polaritons (SPPs) along the metal-dielectric interface.…”