First experimental observation of a full (infinite) momentum bandgap spanning all momenta in a photonic time crystal, achieved via resonant enhancement in two modulated microwave metamaterial platforms.
Resonant states of structured photonic time crystals
4 Pith papers cite this work. Polarity classification is still indexing.
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Pith papers citing it
abstract
Photonic time crystals (PTCs) are spatially uniform media with periodic modulation in time, enabling momentum bandgaps and the parametric amplification of light. While their potential in optical systems is very promising, practical implementations require temporally modulating nanostructures of finite size, for which the physics is no longer governed by bulk properties but by resonant states, or quasinormal modes. Despite their importance, a quantitative theory describing the dynamics of these modes has been missing -- a gap we address here by developing a comprehensive resonant state theory for PTCs with arbitrary geometry. Our framework provides a detailed understanding of the resonant behavior of "structured" PTCs and uncovers several fundamental phenomena. For weak modulations, we find a universal quadratic dependence of the eigenfrequencies on the modulation amplitude. Moreover, each static resonant state gives rise to an infinite ladder of new eigenmodes, spaced by integer multiples of the modulation frequency. Crucially, we show that parametric amplification in these systems arises from a fundamentally resonant process, not captured by the momentum bandgap picture of "bulk" PTCs. We apply our theory to a realistic Bragg microcavity, demonstrating the design of tailored parametric resonances. Due to its generality and predictive power, our approach lays the foundation for the systematic study and engineering of structured PTCs, advancing the emerging field of space-time optics.
citation-role summary
background 1
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fields
physics.optics 4years
2026 4verdicts
UNVERDICTED 4roles
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background 1representative citing papers
A first-order Born theory maps time-modulated scattering amplitudes directly to static-mode overlap integrals, enabling modal control of inelastic channels in dielectric resonators.
Non-Hermitian Berry phases in time-varying media have a quantized real part due to symmetry, giving a topological index for systems including a non-Hermitian Su-Schrieffer-Heeger model.
A focused review organizing literature on quantum photonic time crystals from temporal boundaries and Floquet spectra to light-matter dynamics.
citing papers explorer
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Observation of full momentum bandgap in photonic time crystals
First experimental observation of a full (infinite) momentum bandgap spanning all momenta in a photonic time crystal, achieved via resonant enhancement in two modulated microwave metamaterial platforms.
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Perturbative Born theory for light scattering by time-modulated scatterers
A first-order Born theory maps time-modulated scattering amplitudes directly to static-mode overlap integrals, enabling modal control of inelastic channels in dielectric resonators.
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Partial Quantisation of Non-Hermitian Berry Phases in Time-Varying Media
Non-Hermitian Berry phases in time-varying media have a quantized real part due to symmetry, giving a topological index for systems including a non-Hermitian Su-Schrieffer-Heeger model.
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Quantum Photonic Time Crystals: From Temporal Boundaries to Floquet Light-Matter Interactions
A focused review organizing literature on quantum photonic time crystals from temporal boundaries and Floquet spectra to light-matter dynamics.