Topological photonic cavities based on dissimilar Bragg gratings
Abstract
Topological photonic cavities offer a powerful route to robust optical confinement and enhanced light-matter interactions. Interface states that emerge at the boundary between one-dimensional periodic structures with distinct topological phases, enable cavities with ultra-small mode volumes and intrinsic protection against disorder. Existing implementations typically create the trivial and topological phases by redefining the unit cell on either side of the cavity, so that both periodic structures share the same band structure. This constraint limits design flexibility and the range of accessible devices. Here we introduce a fundamentally different strategy for realizing topological cavities based on combining periodic waveguides with distinct band structures. By exploiting bandgap closing and band inversion in Bragg gratings, we independently control the topological phase and bandgap width of each structure. We experimentally realize silicon topological cavities formed by two different Bragg gratings without period shifting, and observe topological modes despite significant differences between the two gratings. Our results establish a new route to topological photonic cavity design, demonstrating that band inversion between dissimilar Bragg gratings enables cavity formation beyond symmetric constraints and provides a mechanism to engineer optical confinement via mirror asymmetry.
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BibTeX
@misc{sanchezsanchez2026topological,
title = {{Topological photonic cavities based on dissimilar Bragg gratings}},
author = {Alejandro Sánchez-Sánchez and José Manuel Luque-González and Gauthier Krizman and Dorian Oser and Paula Nuño Ruano and David González-Andrade and David Medina Quiroz and Samson Edmond and Alejandro Ortega-Moñux and Jens H. Schmid and Pavel Cheben and Laurent Vivien and Iñigo Molina-Fernández and J. Gonzalo Wangüemert-Pérez and Carlos Alonso-Ramos},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.18362},
eprint = {2609.18362},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.18362},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Topological photonic cavities based on dissimilar Bragg gratings
AU - Alejandro Sánchez-Sánchez
AU - José Manuel Luque-González
AU - Gauthier Krizman
AU - Dorian Oser
AU - Paula Nuño Ruano
AU - David González-Andrade
AU - David Medina Quiroz
AU - Samson Edmond
AU - Alejandro Ortega-Moñux
AU - Jens H. Schmid
AU - Pavel Cheben
AU - Laurent Vivien
AU - Iñigo Molina-Fernández
AU - J. Gonzalo Wangüemert-Pérez
AU - Carlos Alonso-Ramos
PY - 2026
DA - 2026/09/16
PB - arXiv
DO - 10.48550/arxiv.2609.18362
UR - https://arxiv.org/abs/2609.18362
AB - Topological photonic cavities offer a powerful route to robust optical confinement and enhanced light-matter interactions. Interface states that emerge at the boundary between one-dimensional periodic structures with distinct topological phases, enable cavities with ultra-small mode volumes and intrinsic protection against disorder. Existing implementations typically create the trivial and topological phases by redefining the unit cell on either side of the cavity, so that both periodic structures share the same band structure. This constraint limits design flexibility and the range of accessible devices. Here we introduce a fundamentally different strategy for realizing topological cavities based on combining periodic waveguides with distinct band structures. By exploiting bandgap closing and band inversion in Bragg gratings, we independently control the topological phase and bandgap width of each structure. We experimentally realize silicon topological cavities formed by two different Bragg gratings without period shifting, and observe topological modes despite significant differences between the two gratings. Our results establish a new route to topological photonic cavity design, demonstrating that band inversion between dissimilar Bragg gratings enables cavity formation beyond symmetric constraints and provides a mechanism to engineer optical confinement via mirror asymmetry.
ER -