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Main Authors: Yu, Youxiu, Xu, Xiaofeng, Long, Yang, Liu, Gui-Geng, Gao, Dongliang, Lin, Xiao, Hu, Hao
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2604.02076
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author Yu, Youxiu
Xu, Xiaofeng
Long, Yang
Liu, Gui-Geng
Gao, Dongliang
Lin, Xiao
Hu, Hao
author_facet Yu, Youxiu
Xu, Xiaofeng
Long, Yang
Liu, Gui-Geng
Gao, Dongliang
Lin, Xiao
Hu, Hao
contents Guided mode resonance (GMR), the resonant coupling of free-space light into leaky waveguide modes, is traditionally achieved with periodic patterned structures. However, this approach makes its key properties such as quality factor (Q-factor) fabrication-dependent and non-tunable. Here, we introduce a time grating platform, i.e., a homogeneous waveguide whose refractive index is modulated periodically in time, that allows tunable GMRs through temporal modulation engineering rather than spatial structural redesign. We show that the Q-factors of these GMRs diverge as the modulation depth vanishes. Furthermore, unconstrained by energy conservation, the resonances exhibit near-unity reflection for fundamental harmonics and values exceeding 40 for first-order harmonics. Our findings not only apply to yield a giant Goos-Hänchen shift over 103 times wavelength without sacrificing the reflection magnitude, but also open new avenues for related phenomena such as bound states in the continuum, unidirectional GMRs and beyond.
format Preprint
id arxiv_https___arxiv_org_abs_2604_02076
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A time grating approach to ultrahigh-Q guided mode resonance
Yu, Youxiu
Xu, Xiaofeng
Long, Yang
Liu, Gui-Geng
Gao, Dongliang
Lin, Xiao
Hu, Hao
Optics
Guided mode resonance (GMR), the resonant coupling of free-space light into leaky waveguide modes, is traditionally achieved with periodic patterned structures. However, this approach makes its key properties such as quality factor (Q-factor) fabrication-dependent and non-tunable. Here, we introduce a time grating platform, i.e., a homogeneous waveguide whose refractive index is modulated periodically in time, that allows tunable GMRs through temporal modulation engineering rather than spatial structural redesign. We show that the Q-factors of these GMRs diverge as the modulation depth vanishes. Furthermore, unconstrained by energy conservation, the resonances exhibit near-unity reflection for fundamental harmonics and values exceeding 40 for first-order harmonics. Our findings not only apply to yield a giant Goos-Hänchen shift over 103 times wavelength without sacrificing the reflection magnitude, but also open new avenues for related phenomena such as bound states in the continuum, unidirectional GMRs and beyond.
title A time grating approach to ultrahigh-Q guided mode resonance
topic Optics
url https://arxiv.org/abs/2604.02076