qBIC-Enhanced True Chiral Nonlinear Response in a Monolayer WS₂ Hybrid Metasurface

Gaojing Liu; Ziming Meng

doi:10.54097/8gk7zc36

Authors

Gaojing Liu
Ziming Meng

DOI:

https://doi.org/10.54097/8gk7zc36

Keywords:

True Chirality, Bound States in the Continuum, Dielectric Metasurfaces, WS₂, Nonlinear Frequency Conversion, Circular Dichroism

Abstract

Hybrid dielectric metasurfaces that combine true chirality, quasi-bound states in the continuum (qBICs), and the strong second-order nonlinearity of two-dimensional semiconductors provide an efficient route toward chirality-selective nonlinear optics. Based on the supplied simulation results, this paper presents a systematic analysis of a truly chiral G-shaped metasurface composed of TiO₂, SiO₂, and WS₂. The structure breaks symmetry through its planar G-shaped geometry, vertical layered stacking, and a 10° perturbation, thereby transforming an originally symmetry-protected bound state in the continuum into an externally excitable qBIC mode. As a result, a high-Q resonance, pronounced circular dichroism, and strong near-field localization emerge around 794.7 nm. The circularly polarized transmission spectra indicate strong spin-selective coupling, while the magnetic-field maps further reveal markedly different hotspot patterns near the active interface under opposite helicities. When combined with the second-order polarization response of WS₂, the device exhibits an approximately 29.2-fold helicity contrast in nonlinear frequency conversion. The physical mechanisms reflected in each figure are further clarified from the perspectives of multipolar interference, coupled-mode physics, and field-material overlap. Taken together, the dataset forms a coherent scientific narrative: geometric symmetry breaking opens the qBIC channel, true chirality endows the resonance with helicity selectivity, and the localized resonant field enhances the second-order nonlinearity of WS₂, ultimately enabling highly selective nonlinear conversion.

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References

[1] C. W. Hsu, B. Zhen, A. D. Stone, J. D. Joannopoulos, and M. Soljačić. Bound states in the continuum. Nature Reviews Materials 2016, 1, 16048.

[2] K. Koshelev, S. Lepeshov, M. Liu, A. Bogdanov, and Y. Kivshar. Asymmetric metasurfaces with high-Q resonances governed by bound states in the continuum. Physical Review Letters 2018, 121(19), 193903.

[3] L. Carletti, K. Koshelev, C. De Angelis, and Y. Kivshar. Giant nonlinear response at the nanoscale driven by bound states in the continuum. Physical Review Letters 2018, 121(3), 033903.

[4] M.-S. Hwang, K.-Y. Jeong, J.-P. So, K.-H. Kim, and H.-G. Park. Nanophotonic nonlinear and laser devices exploiting bound states in the continuum. Communications Physics 2022, 5(1), 106.

[5] Y. Tang and A. E. Cohen. Optical chirality and its interaction with matter. Physical Review Letters 2010, 104(16), 163901.

[6] H. S. Khaliq, A. Nauman, J.-W. Lee, and H.-R. Kim. Recent progress on plasmonic and dielectric chiral metasurfaces: fundamentals, design strategies, and implementation. Advanced Optical Materials 2023, 11, 2300644.

[7] L. Kühner, F. J. Wendisch, A. A. Antonov, J. Bürger, L. Hüttenhofer, L. de S. Menezes, S. A. Maier, M. V. Gorkunov, Y. Kivshar, and A. Tittl. Unlocking the out-of-plane dimension for photonic bound states in the continuum to achieve maximum optical chirality. Light: Science & Applications 2023, 12, 250.

[8] K. Koshelev, Y. Tang, Z. Hu, I. I. Kravchenko, G. Li, and Y. Kivshar. Resonant chiral effects in nonlinear dielectric metasurfaces. ACS Photonics 2023, 10(1), 298-306.

[9] N. Kumar, S. Najmaei, Q. Cui, F. Ceballos, P. M. Ajayan, J. Lou, and H. Zhao. Second harmonic microscopy of monolayer MoS2. Physical Review B 2013, 87(16), 161403(R).

[10] C. Janisch, Y. Wang, D. Ma, N. Mehta, A. L. Elías, N. Perea-López, M. Terrones, V. Crespi, and Z. Liu. Extraordinary second harmonic generation in tungsten disulfide monolayers. Scientific Reports 2014, 4, 5530.

[11] G. T. Forcherio, J. Riporto, J. R. Dunklin, Y. Mugnier, R. Le Dantec, L. Bonacina, and D. K. Roper. Nonlinear optical susceptibility of two-dimensional WS2 measured by hyper-Rayleigh scattering. Optics Letters 2017, 42(23), 5018-5021.

[12] K. Bredillet, J. Riporto, G. T. Forcherio, J. R. Dunklin, J.-P. Wolf, L. Bonacina, Y. Mugnier, and R. Le Dantec. Dispersion of the nonlinear susceptibility of MoS2 and WS2 from second-harmonic scattering spectroscopy. Physical Review B 2020, 102(23), 235408.

[13] N. Bernhardt, K. Koshelev, S. J. U. White, K. W. C. Meng, J. E. Fröch, S. Kim, T. T. Tran, D.-Y. Choi, Y. Kivshar, and A. S. Solntsev. Quasi-BIC resonant enhancement of second-harmonic generation in WS2 monolayers. Nano Letters 2020, 20(7), 5309-5314.

[14] V. Kravtsov, E. Khestanova, F. A. Benimetskiy, T. S. Ivanova, A. P. Samusev, I. S. Sinev, D. G. Pidgayko, A. S. Mozharov, I. S. Mukhin, M. S. Lozhkin, Y. V. Kapitonov, A. S. Brichkin, M. V. Petrov, V. S. Volkov, D. N. Krizhanovskii, I. V. Iorsh, and A. N. Grigorenko. Nonlinear polaritons in a monolayer semiconductor coupled to optical bound states in the continuum. Light: Science & Applications 2020, 9, 56.

[15] E. Maggiolini, L. Polimeno, F. Todisco, A. Di Renzo, B. Han, M. De Giorgi, V. Ardizzone, C. Schneider, R. Mastria, A. Cannavale, M. Pugliese, L. De Marco, A. Rizzo, V. Maiorano, G. Gigli, D. Gerace, D. Sanvitto, and D. Ballarini. Strongly enhanced light-matter coupling of monolayer WS2 from a bound state in the continuum. Nature Materials 2023, 22(8), 964-969.