Photonic time crystals assisted by quasi-bound states in the continuum

Puneet Garg; Evangelos Almpanis; Leander Zimmer; Jan David Fischbach; Xuchen Wang; Mohammad S. Mirmoosa; Markus Nyman; Nikolaos Stefanou; Nikolaos Papanikolaou; Viktar Asadchy; Carsten Rockstuhl

doi:10.1126/sciadv.aed4055

Photonic time crystals assisted by quasi-bound states in the continuum

Puneet Garg
, Evangelos Almpanis
, Leander Zimmer
, Jan David Fischbach
, Xuchen Wang
, Mohammad S. Mirmoosa
, Markus Nyman
, Nikolaos Stefanou
, Nikolaos Papanikolaou
, Viktar Asadchy
, Carsten Rockstuhl

Karlsruhe Institute of Technology
National and Kapodistrian University of Athens
Harbin Engineering University
University of Eastern Finland

Research output: Contribution to journal › Article › Scientific › peer-review

1 Downloads (Pure)

Abstract

Photonic time crystals (PTCs) are characterized by the rapid modulation of the material properties in time, causing a momentum bandgap for light. However, the observation of these bandgaps at optical frequencies remains elusive as the necessary temporal modulation amplitudes to show notable momentum bandgaps are relatively high, inaccessible with available materials. While it has been known that structuring PTCs at the subwavelength scale can improve the bandgap size, we push this concept to the extreme by leveraging the nanophotonic toolbox. Specifically, we demonstrate that structures composed of scatterers supporting quasi-bound states in the continuum can substantially reduce the required modulation amplitudes by enhancing the interaction time between light and time-varying matter. This allows us to observe noticeable momentum bandgaps despite the weak temporal modulation. Our approach bridges the concepts of bound states in the continuum and time-varying metamaterials, paving the way toward realizable PTCs at optical frequencies.

Original language	English
Article number	eaed4055
Pages (from-to)	eaed4055
Journal	Science Advances
Volume	12
Issue number	33
DOIs	https://doi.org/10.1126/sciadv.aed4055
Publication status	Published - 12 Aug 2026
MoE publication type	A1 Journal article-refereed

Funding

V.A. acknowledges the Finnish Foundation for Technology Promotion, and Research Council of Finland Flagship Programme, Photonics Research and Innovation (PREIN), decision number 346529, Aalto University. X.W. acknowledges the Fundamental Research Funds for the Central Universities, China (project no. 3072024WD2603). P.G. and C.R. are part of the Max Planck School of Photonics, supported by the Bundesministerium für Bildung und Forschung, the Max Planck Society, and the Fraunhofer Society. P.G. and C.R. acknowledge support by the German Research Foundation within the SFB 1173 (project ID no. 258734477). P.G. and J.D.F. acknowledge support from the Karlsruhe School of Optics and Photonics (KSOP). M.N. and C.R. acknowledge support by the KIT through the “Virtual Materials Design” (VIRTMAT) project. J.D.F. and C.R. acknowledge financial support by the Helmholtz Association in the framework of the innovation platform “Solar TAP.” We acknowledge support by the KIT Publication Fund of the Karlsruhe Institute of Technology.

Access to Document

10.1126/sciadv.aed4055Licence: CC BY

Photonic_time_crystals_assisted_by_quasi-boundFinal published version, 3.62 MBLicence: CC BY

Cite this

@article{8bfa145bd8a74dd6ba4b9c9fc5e22b4a,

title = "Photonic time crystals assisted by quasi-bound states in the continuum",

abstract = "Photonic time crystals (PTCs) are characterized by the rapid modulation of the material properties in time, causing a momentum bandgap for light. However, the observation of these bandgaps at optical frequencies remains elusive as the necessary temporal modulation amplitudes to show notable momentum bandgaps are relatively high, inaccessible with available materials. While it has been known that structuring PTCs at the subwavelength scale can improve the bandgap size, we push this concept to the extreme by leveraging the nanophotonic toolbox. Specifically, we demonstrate that structures composed of scatterers supporting quasi-bound states in the continuum can substantially reduce the required modulation amplitudes by enhancing the interaction time between light and time-varying matter. This allows us to observe noticeable momentum bandgaps despite the weak temporal modulation. Our approach bridges the concepts of bound states in the continuum and time-varying metamaterials, paving the way toward realizable PTCs at optical frequencies.",

author = "Puneet Garg and Evangelos Almpanis and Leander Zimmer and Fischbach, \{Jan David\} and Xuchen Wang and Mirmoosa, \{Mohammad S.\} and Markus Nyman and Nikolaos Stefanou and Nikolaos Papanikolaou and Viktar Asadchy and Carsten Rockstuhl",

year = "2026",

month = aug,

day = "12",

doi = "10.1126/sciadv.aed4055",

language = "English",

volume = "12",

pages = "eaed4055",

journal = "Science Advances",

issn = "2375-2548",

publisher = "American Association for the Advancement of Science",

number = "33",

}

TY - JOUR

T1 - Photonic time crystals assisted by quasi-bound states in the continuum

AU - Garg, Puneet

AU - Almpanis, Evangelos

AU - Zimmer, Leander

AU - Fischbach, Jan David

AU - Wang, Xuchen

AU - Mirmoosa, Mohammad S.

AU - Nyman, Markus

AU - Stefanou, Nikolaos

AU - Papanikolaou, Nikolaos

AU - Asadchy, Viktar

AU - Rockstuhl, Carsten

PY - 2026/8/12

Y1 - 2026/8/12

N2 - Photonic time crystals (PTCs) are characterized by the rapid modulation of the material properties in time, causing a momentum bandgap for light. However, the observation of these bandgaps at optical frequencies remains elusive as the necessary temporal modulation amplitudes to show notable momentum bandgaps are relatively high, inaccessible with available materials. While it has been known that structuring PTCs at the subwavelength scale can improve the bandgap size, we push this concept to the extreme by leveraging the nanophotonic toolbox. Specifically, we demonstrate that structures composed of scatterers supporting quasi-bound states in the continuum can substantially reduce the required modulation amplitudes by enhancing the interaction time between light and time-varying matter. This allows us to observe noticeable momentum bandgaps despite the weak temporal modulation. Our approach bridges the concepts of bound states in the continuum and time-varying metamaterials, paving the way toward realizable PTCs at optical frequencies.

AB - Photonic time crystals (PTCs) are characterized by the rapid modulation of the material properties in time, causing a momentum bandgap for light. However, the observation of these bandgaps at optical frequencies remains elusive as the necessary temporal modulation amplitudes to show notable momentum bandgaps are relatively high, inaccessible with available materials. While it has been known that structuring PTCs at the subwavelength scale can improve the bandgap size, we push this concept to the extreme by leveraging the nanophotonic toolbox. Specifically, we demonstrate that structures composed of scatterers supporting quasi-bound states in the continuum can substantially reduce the required modulation amplitudes by enhancing the interaction time between light and time-varying matter. This allows us to observe noticeable momentum bandgaps despite the weak temporal modulation. Our approach bridges the concepts of bound states in the continuum and time-varying metamaterials, paving the way toward realizable PTCs at optical frequencies.

UR - https://www.scopus.com/pages/publications/105047160228

U2 - 10.1126/sciadv.aed4055

DO - 10.1126/sciadv.aed4055

M3 - Article

C2 - 42585339

AN - SCOPUS:105047160228

SN - 2375-2548

VL - 12

SP - eaed4055

JO - Science Advances

JF - Science Advances

IS - 33

M1 - eaed4055

ER -

Photonic time crystals assisted by quasi-bound states in the continuum

Abstract

Funding

Access to Document

Other files and links

Fingerprint

PREIN 2: Photonics Research and Innovation

Micro-electronics, Digital and Autonomous Systems (MIDAS)

Cite this

Photonic time crystals assisted by quasi-bound states in the continuum

Abstract

Funding

Access to Document

Other files and links

Fingerprint

Projects

PREIN 2: Photonics Research and Innovation

Equipment

Micro-electronics, Digital and Autonomous Systems (MIDAS)

Cite this