{"paper":{"title":"Tunable high-$Q$ Janus-to-chiral bound states in the continuum in bilayer PhCs","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Symmetry-selective displacements in bilayer photonic crystals convert Janus bound states into tunable high-Q chiral resonances.","cross_cats":[],"primary_cat":"physics.optics","authors_text":"Haiyu Meng, Shengxuan Xia, Yee Sin Ang, Zhexing Dong","submitted_at":"2026-05-14T05:55:36Z","abstract_excerpt":"We propose a bilayer all-dielectric PhC for controlling Janus bound states in the continuum (BIC) and optical chirality through symmetry-selective perturbations. Starting from a symmetry-protected $\\Gamma$-point BIC, we use interlayer displacement as one geometric control knob to generate different topological charges in the upward radiation and downward radiation channels. A subsequent diagonal in-plane displacement reconstructs the polarization topology around the BIC and generates a Janus-chiral BIC with strong handedness selectivity. In contrast, other in-plane perturbations generate chira"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"We further show that material conductivity provides an additional dissipative degree of freedom for actively modulating the chiral response, with a switchable CD exceeding 0.89.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The assumption that the proposed symmetry-selective perturbations (interlayer and diagonal in-plane displacements) preserve high-Q factors while enabling strong chirality in fabricated structures, without significant scattering losses from imperfections.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Bilayer all-dielectric photonic crystals with interlayer and diagonal in-plane displacements generate tunable high-Q Janus-chiral bound states in the continuum, achieving switchable circular dichroism exceeding 0.89 via conductivity modulation.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Symmetry-selective displacements in bilayer photonic crystals convert Janus bound states into tunable high-Q chiral resonances.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"84129490cd8c4d5426e8d5b9f754f88af78f906324481d02d51ca1fb3ecf7390"},"source":{"id":"2605.14412","kind":"arxiv","version":1},"verdict":{"id":"ca7174ed-e83c-44e8-ba33-801cb729fa90","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-15T02:13:31.106164Z","strongest_claim":"We further show that material conductivity provides an additional dissipative degree of freedom for actively modulating the chiral response, with a switchable CD exceeding 0.89.","one_line_summary":"Bilayer all-dielectric photonic crystals with interlayer and diagonal in-plane displacements generate tunable high-Q Janus-chiral bound states in the continuum, achieving switchable circular dichroism exceeding 0.89 via conductivity modulation.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The assumption that the proposed symmetry-selective perturbations (interlayer and diagonal in-plane displacements) preserve high-Q factors while enabling strong chirality in fabricated structures, without significant scattering losses from imperfections.","pith_extraction_headline":"Symmetry-selective displacements in bilayer photonic crystals convert Janus bound states into tunable high-Q chiral resonances."},"references":{"count":78,"sample":[{"doi":"","year":2008,"title":"D. C. Marinica, A. G. Borisov, and S. V. Shabanov, Phys- ical Review Letters100, 183902 (2008)","work_id":"e17ec4f2-1eb5-44d5-a990-55b2a666b0f0","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2016,"title":"C. W. Hsu, B. Zhen, A. D. Stone, J. D. Joannopou- los, and M. Soljaˇ ci´ c, Nature Reviews Materials1, 16048 (2016)","work_id":"760753b3-31f2-4d78-847b-927344196442","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2023,"title":"M. Kang, T. Liu, C. T. Chan, and M. Xiao, Nature Re- views Physics5, 659 (2023)","work_id":"c3b18125-333a-4476-8f97-a14cf1a6950f","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2024,"title":"J. Wang, P. Li, X. Zhao, Z. Qian, X. Wang, F. Wang, X. Zhou, D. Han, L. Shi, and J. Zi, Photonics Insights3, R01 (2024)","work_id":"1b2a0a09-fba1-424d-994b-8009f2ad750c","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2021,"title":"M. Kang, S. Zhang, M. Xiao, and H. Xu, Physical Review Letters126, 117402 (2021)","work_id":"39336fa2-3da3-4ee1-814a-565d54655f1d","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":78,"snapshot_sha256":"6323aa3e6c93f8783fd593cf2643cb5b84e02aae19d2c0ee340b2a18df960860","internal_anchors":0},"formal_canon":{"evidence_count":2,"snapshot_sha256":"04abb9866b0f28a7ae167b943114eb772962a09c948c7b71b139ee6c43221d67"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}