Low-Contrast BIC Metasurfaces with Quality Factors Exceeding 100,000

Fuente: arXiv
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Main Authors: Watanabe, Keisuke, Nagao, Tadaaki, Iwanaga, Masanobu
Format: Preprint
Published: 2024
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author Watanabe, Keisuke
Nagao, Tadaaki
Iwanaga, Masanobu
author_facet Watanabe, Keisuke
Nagao, Tadaaki
Iwanaga, Masanobu
contents Dielectric metasurfaces operating at quasi-bound states in the continuum (qBICs) can achieve exceptionally high radiative quality ($\textit{Q}$) factors by introducing small asymmetries into their unit cells. However, fabrication imperfections often impose major limitations on the experimentally observed $\textit{Q}$ factors. In this study, we experimentally demonstrate BIC metasurfaces with a record-high $\textit{Q}$ factor of 101,486 under normal excitation of light in the telecom wavelength range achieved by employing low-contrast silicon pairs. Our findings show that such ultrahigh-$\textit{Q}$ factors can be attained by leveraging both the high radiative $\textit{Q}$ factors of higher-order qBIC modes and reduced scattering losses in shallow-etched designs. Additionally, we demonstrate stable sub-picometer-level wavelength fluctuations in water, with a limit of detection of $10^{-5}$ for environmental refractive index changes. The proposed approach can be extended to BIC metasurfaces with many other configurations and operating wavelengths for ultrahigh-$\textit{Q}$ applications in both fundamental physics and advanced devices.
format Preprint
id arxiv_https___arxiv_org_abs_2411_14101
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Low-Contrast BIC Metasurfaces with Quality Factors Exceeding 100,000
Watanabe, Keisuke
Nagao, Tadaaki
Iwanaga, Masanobu
Optics
Applied Physics
Dielectric metasurfaces operating at quasi-bound states in the continuum (qBICs) can achieve exceptionally high radiative quality ($\textit{Q}$) factors by introducing small asymmetries into their unit cells. However, fabrication imperfections often impose major limitations on the experimentally observed $\textit{Q}$ factors. In this study, we experimentally demonstrate BIC metasurfaces with a record-high $\textit{Q}$ factor of 101,486 under normal excitation of light in the telecom wavelength range achieved by employing low-contrast silicon pairs. Our findings show that such ultrahigh-$\textit{Q}$ factors can be attained by leveraging both the high radiative $\textit{Q}$ factors of higher-order qBIC modes and reduced scattering losses in shallow-etched designs. Additionally, we demonstrate stable sub-picometer-level wavelength fluctuations in water, with a limit of detection of $10^{-5}$ for environmental refractive index changes. The proposed approach can be extended to BIC metasurfaces with many other configurations and operating wavelengths for ultrahigh-$\textit{Q}$ applications in both fundamental physics and advanced devices.
title Low-Contrast BIC Metasurfaces with Quality Factors Exceeding 100,000
topic Optics
Applied Physics
url https://arxiv.org/abs/2411.14101