Polaritonic coherent perfect absorption based on self-hybridization of a quasi-bound state in the continuum and exciton

Abstract

Enhancement of light-matter interactions is of great importance for many nanophotonic devices, and one way to achieve it is to feed energy perfectly to the strongly coupled system. Here, we propose gap-perturbed dimerized gratings based on bulk WS2 for flexible control of the strong coupling or self-hybridization of a quasi-bound state in the continuum (quasi-BIC) and exciton. The simulation results show that when a gap perturbation is introduced into the system resulting in the Brillouin zone folding, BIC transforms into quasi-BIC whose quality factor (Q-factor) is related to the value of gap perturbation. The strong coupling results in the anti-crossover behavior of the absorption spectra, and thus a Rabi splitting energy of 0.235 eV is obtained. With the assistance of temporal coupled-mode theory, the conditions for the strong critical coupling are obtained, and finally successful achievement of polaritonic coherent perfect absorption in the proposed system. This work could provide ideas for enhancing light-matter interactions and strong theoretical support for all-optical tuning and modulation.

The impact of regional economic integration on CO2 emissions in the Changsha-Zhuzhou-Xiangtan urban agglomeration, China

“…The resonance wavelength of BIC is 1106 nm, and the near field distribution E y indicates that it concentrates around high-dielectric material rather than the air gap. When the perturbation δ is introduced, the BIC will transfer into quasi-BIC with finite quality factor Q and non-zero linewidth, and its formation mechanism could be attributed to the Brillouin zone folding [6]. The transmission spectra with varying perturbation δ are presented in Fig.…”

“…In 1929, John von Neumann and Wigner introduced the concept of BIC as a solution to the single-particle Schrödinger equation in quantum mechanics [1]. BIC has been applied in various systems, such as fluid dynamics, acoustics, electromagnetic waves, and water waves [2][3][4][5][6][7][8][9][10][11]. Recently, photonic nanostructures have become a suitable platform for investigating the properties of BICs, paving the way for potential applications in low-loss lasers, sensors, and filters [12][13][14][15][16].…”

Optical bound states in the continuum in periodic structures: mechanisms, effects, and applications

“…Besides using the TMDC monolayer over or inside the periodic structures [151–156] , fabricating bulk TMDC materials to form metasurfaces can efficiently improve the spatial overlap of the cavity mode profile with the emitters to make more significant strength of light–matter interaction. While several theoretical bulk WS2 works give large Rabi splitting that even exceeds 200 meV [157–161] , recent experiments show a tuned strong coupling system with maximum Rabi splitting of 116 meV by constructing BIC-driven metasurfaces composed of bulk WS2 [162] . Besides TMDC materials, perovskite metasurfaces are also worth trying to enhance the strength of light–matter interaction.…”

Large Rabi splitting energy in resonant quasi-BIC WSe2 metasurfaces

“…For instance, in 2021, Zong et al achieved a Rabi splitting of 120 meV by strong coupling QBIC modes to excitons in a WS 2 bulk material [39]. In 2022, Gu et al increased the Rabi splitting to 235 meV using the similar scheme [40]. In 2023, Xie et al achieved a remarkable Rabi splitting of up to 464 meV, demonstrated that the self-hybridized BIC-X coupling strength in this 2D metasurface can be dramatically enhanced with the assistance of a Fabry-Pérot cavity, which represents the highest Rabi splitting value in current strong coupling studies [41].…”