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12 pages, 6663 KB

Open AccessArticle

Tuning Q-Factor and Perfect Absorption Using Coupled Tamm States on Polarization-Preserving Metasurface

by Natalya V. Rudakova, Rashid G. Bikbaev, Larisa E. Tyryshkina, Stepan Ya. Vetrov and Ivan V. Timofeev

Photonics 2023, 10(12), 1391; https://doi.org/10.3390/photonics10121391 - 18 Dec 2023

Cited by 2 | Viewed by 2678

Abstract

The circular polarization of light flips its handedness after a conventional metallic mirror reflection. Therefore, a polarization-preserving metasurface is a crucially important element in a series of chiral photonic structures. They include tunable cholesteric LCs and anisotropic photonic crystals. Chiral structures are rich in interfacial localized modes including Tamm states. In this report, coupled modes formed as a result of the interaction between two chiral optical Tamm states or a chiral optical Tamm state and a chiral Tamm plasmon polariton are analytically and numerically investigated. It is shown that the effective control of coupled modes can be carried out by changing the pitch of the cholesteric and the angle between the optical axis of the cholesteric and the polarization-preserving anisotropic mirror. The influence of the metasurface period on the spectral characteristics of coupled modes is investigated. The possibility of realizing a bound state in the continuum of the Friedrich–Wintgen type, resulting from the destructive interference of coupled modes, which leads to the collapse of the resonance line corresponding to the chiral optical Tamm state, has been demonstrated. Full article

(This article belongs to the Special Issue Multifunctional Metasurfaces: Design Strategies and Applications)

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8 pages, 3301 KB

Open AccessArticle

Metal–Dielectric Polarization-Preserving Anisotropic Mirror for Chiral Optical Tamm State

by Natalya V. Rudakova, Rashid G. Bikbaev, Pavel S. Pankin, Stepan Ya. Vetrov, Ivan V. Timofeev, Kuo-Ping Chen and Wei Lee

Nanomaterials 2022, 12(2), 234; https://doi.org/10.3390/nano12020234 - 12 Jan 2022

Cited by 5 | Viewed by 2766

Abstract

This numerical study demonstrates the possibility of exciting a chiral optical Tamm state localized at the interface between a cholesteric liquid crystal and a polarization-preserving anisotropic mirror conjugated to a metasurface. The difference of the proposed structure from a fully dielectric one is that the metasurface makes it possible to decrease the number of layers of a polarization-preserving anisotropic mirror by a factor of more than two at the retained Q-factor of the localized state. It is shown that the proposed structure can be used in a vertically emitting laser. Full article

(This article belongs to the Section Nanophotonics Materials and Devices)

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10 pages, 1202 KB

Open AccessArticle

Chiral Optical Tamm States at the Interface between a Dye-Doped Cholesteric Liquid Crystal and an Anisotropic Mirror

by Anastasia Yu. Avdeeva, Stepan Ya. Vetrov, Rashid G. Bikbaev, Maxim V. Pyatnov, Natalya V. Rudakova and Ivan V. Timofeev

Materials 2020, 13(15), 3255; https://doi.org/10.3390/ma13153255 - 22 Jul 2020

Cited by 5 | Viewed by 2816

Abstract

The resonant splitting of optical Tamm state numerically is demonstrated. The Tamm state is localized at the interface between a resonant chiral medium and a polarization-preserving anisotropic mirror. The chiral medium is considered as a cholesteric liquid crystal doped with resonant dye molecules. The article shows that the splitting occurs when dye resonance frequency coincides with the frequency of the Tamm state. In this case the reflectance, transmittance, and absorptance spectra show two distinct Tamm modes. For both modes, the field localization is at the interface between the media. The external field control of configurable optical and structural parameters paves the way for use in tunable chiral microlaser. Full article

(This article belongs to the Special Issue Soft Photonic Crystals and Metamaterials)

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12 pages, 3215 KB

Open AccessArticle

Chiral Optical Tamm States at the Interface between an All-Dielectric Polarization-Preserving Anisotropic Mirror and a Cholesteric Liquid Crystal

by Natalya V. Rudakova, Ivan V. Timofeev, Rashid G. Bikbaev, Maxim V. Pyatnov, Stepan Ya. Vetrov and Wei Lee

Crystals 2019, 9(10), 502; https://doi.org/10.3390/cryst9100502 - 26 Sep 2019

Cited by 13 | Viewed by 4568

Abstract

As a new localized state of light, the chiral optical Tamm state exists at the interface between a polarization-retaining anisotropic mirror and a substance with optical activity. Considering a hybrid structure comprising a metal-free polarization-preserving mirror and a cholesteric liquid crystal, we highlight the high Q factor arising from the all-dielectric framework. The intensity of localized light decreases exponentially with increasing distance from the interface. The penetration of the field into the cholesteric liquid crystal is essentially prohibited for wavelengths lying in the photonic bandgap and close to the cholesteric pitch length. The dielectric mirror has its own photonic bandgap. The energy transfer along the interface can be effectively switched off by setting the tangential wave vector to zero. The spectral behavior of the chiral optical Tamm state is observed both as reflection and transmission resonance. This Fano resonance is analogous to the Kopp–Genack effect. Our analytics are well in line with precise calculations, which may pave a new route for the future development of intelligent design for laser and sensing applications. Full article

(This article belongs to the Special Issue Localized Optical Modes in Liquid Crystals)

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9 pages, 1375 KB

Open AccessArticle

Coupled Chiral Optical Tamm States in Cholesteric Liquid Crystals

by Maxim V. Pyatnov, Ivan V. Timofeev, Stepan Ya. Vetrov and Natalya V. Rudakova

Photonics 2018, 5(4), 30; https://doi.org/10.3390/photonics5040030 - 28 Sep 2018

Cited by 4 | Viewed by 4517

Abstract

The modes formed by two coupled chiral optical Tamm states localized at the interfaces between a photonic cholesteric liquid crystal conjugated with polarization-preserving anisotropic mirrors have been analytically and numerically investigated. These modes are only excited at the diffracting polarization of incident light. As the cholesteric layer thickness decreases, the spectral splitting of the localized state frequency is predicted. The splitting value depends on the crystal layer thickness. At the nondiffracting circular polarization, the localized modes are not excited, and the system becomes similar to the Fabry–Pérot cavity containing an anisotropic helical structure. Full article

(This article belongs to the Special Issue Nonlinear Dielectric Photonics and Metasurfaces)

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