Wavy optical grating: wideband reflector and Fabry-Perot BICs

Ma Luo; Feng Wu

Home/Archive/arXiv

arXiv · 2211.06201

Wavy optical grating: wideband reflector and Fabry-Perot BICs

Ma Luo·Feng Wu

View original source ↗Read source document ↗Export metadata ↓

Abstract

In this study, we theoretically and numerically investigate the resonant modes and reflectance of an optical grating consisting of a wavy dielectric slab by applying the spectral element method. The presence of the wavy shape transforms the waveguide modes into leaky resonant modes. A few resonant modes with specific longitudinal wave number have infinitely large Q factor, while the other resonant modes have finite Q factor. For the leaky resonant mode with zero longitudinal wave number, the Q factor is inversely proportional to the amplitude of the wavy shape. An array of multiple low-Q wavy gratings has a high reflectance in a large bandwidth. A double-layer wavy grating forms a Fabry-Perot cavity, which hosts Fabry-Perot bound states in the continuum (BICs) at the resonant frequency. The Q-factor of the Fabry-Perot cavity can be tuned by adjusting the distance between the two wavy slabs. The wavy shape could be generated by a vibrational wave in a flat dielectric slab so that the BICs mode and wideband reflectance could be controlled on-demand.

Explore related subjects

physics.optics cond-mat.mes-hall

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Ma Luo, Feng Wu. 2022-11-11. Wavy optical grating: wideband reflector and Fabry-Perot BICs. https://arxiv.org/abs/2211.06201

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Nonlinear Magneto-Optical Probing of Time-Reversal Symmetry Breaking

Solid-state harmonic generation provides a nonlinear probe of symmetries encoded in electronic wave functions. In the subgap and weak-injection regime, time reversal pairs the harmonic responses driven by fields of opposite ellipticity, strongly suppressing elliptical dichroism in time-reversal-symmetric crystals. We show that, in a magnetic crystal, spin-orbit coupling transfers time-reversal-symmetry breaking from the spin sector to the orbital wave functions and lifts this pairing through the geometric phases of the electric-dipole current. Semiconductor-Bloch-equation calculations for centrosymmetric bilayer Cr2Ge2Te6 predict pronounced third-harmonic elliptical dichroism that reverses with the magnetization. Under linearly polarized driving, SOC-induced geometric-phase accumulation generates a nonlinear transverse current and strongly enhances the harmonic rotation and ellipticity. These results identify the geometric phase as a key microscopic contribution to the nonlinear magneto-optical response. This work establishes helicity-resolved harmonic emission and nonlinear polarimetry as complementary probes of spin-orbit-coupled magnetic order.

physics.optics↗

arXiv2026

Spatiotemporal topological phase transitions in photonic spacetime crystals

Topological phase transitions have played a central role in topological physics. However, such transitions have so far been restricted to spatial or temporal crystals. Here, we transcend this conventional framework and report, for the first time, spatiotemporal topological phase transitions in photonic spacetime crystals - structures that are periodically modulated in both space and time. In a genuine photonic spacetime crystal composed of a dynamically modulated transmission-line metamaterial, we theoretically propose and experimentally demonstrate complete spatiotemporal topological phase transitions, characterized by the closing and reopening of both energy and momentum band gaps, along with changes in spatiotemporal topological invariants and topological phases. Furthermore, we directly observe a spatiotemporal, topologically localized state that exhibits causality-governed excitation and robustness to spatiotemporal disorders. Our findings reveal the interplay among space, time, and topology, establishing a unified framework that provides a comprehensive picture of the emerging topological spacetime physics and opening new avenues for robust spatiotemporal topological wave manipulations.

physics.optics↗

arXiv2026

High-Resolution Sensing via Quantum States Discrimination

High-resolution sensing plays a significant role in scientific research and industrial production, but the practical implementation is constrained by the physical mechanisms of the sensors. To address the critical limitation, we propose a high-resolution sensing approach based on quantum state discrimination. Distinct from conventional strategies, the proposed approach constructs measurement operators in the orthogonal complement space rather than eigenspace of the eigenstate, thereby notably improving the discriminability among quantum states. Moreover, the experimental results via an optical microcavity demonstrate a potential sensing resolution of 4 $\times$ 10\textsuperscript{-6} \degree C and 18 p$ε$ respectively for temperature and strain, and further verify the feasibility of simultaneous sensing of the two parameters. This work establishs a universal approach for high-resolution sensing, and may be extended to different sensing platforms across various application scenarios.

physics.optics↗