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Zeng R, Wang C, Zeng X, Li H, Yang S, Li Q, Yang Y. Casimir torque and force in anisotropic saturated ferrite three-layer structure. OPTICS EXPRESS 2020; 28:7425-7441. [PMID: 32225971 DOI: 10.1364/oe.386083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 02/21/2020] [Indexed: 06/10/2023]
Abstract
Based on the scattering formalism and transfer matrix method, we calculate the Casimir energy in multilayer system containing general anisotropic media and apply the result to the anisotropic saturated ferrite three-layer structure. We investigate the stable equilibrium resulting from repulsive Casimir force in the three-layer anisotropic ferrite structure, focusing on the control of the equilibrium position by means of the external magnetic field, which might provide possibility for Casimir actuation under external manipulation. Furthermore, we propose a Casimir torque switch where the torque acting on the intermediate layer can be switched on and off by tuning the relative orientation between the external magnetic fields applied on the outer ferrite layers. The relation between the feature of torque-off/torque-on state and the weak/strong anisotropy of the ferrite is studied. These findings suggest potential application of Casimir torque in, e.g., cooling the rotation of a thin slab in micromachining process via external magnetic field.
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Wang Y, Chen J, Liang W, Li ZY. Super-sensitive tunable planar lens based on graphene hyperbolic metamaterials. OPTICS EXPRESS 2019; 27:24738-24746. [PMID: 31510358 DOI: 10.1364/oe.27.024738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 08/02/2019] [Indexed: 06/10/2023]
Abstract
We theoretically study the topological transition of dispersion types and propose a tunable planar lens based on graphene hyperbolic metamaterials (HMMs). By tuning the chemical potential (μc) of graphene, the dispersion relation of the HMM is topologically switchable between ellipse (μc<0.6 eV) and hyperbola (μc>0.6 eV) where positive and negative refractions occur respectively. Especially, for μc>0.6 eV, a Gaussian light beam is negatively refracted twice and focuses at a far-field point finally, acting well as a planar lens. Furthermore, its focal length l can be sensitively tuned by controlling μc, and Δl reaches 260 μm (from 528 to 268 μm) while μc varies with only 0.05 eV (from 0.65 to 0.7 eV). The physical reason is attributed to the different anisotropy degrees of EFCs for different μc. Such a compact, high-speed, and sensitively tunable planar lens holds great promise in photonic integration, photonic imaging, and directional coupling applications.
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Song G, Zeng R, Al-Amri M, Xu J, Zhu C, He P, Yang Y. Repulsive Casimir force between hyperbolic metamaterials. OPTICS EXPRESS 2018; 26:34461-34473. [PMID: 30650869 DOI: 10.1364/oe.26.034461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/21/2018] [Indexed: 06/09/2023]
Abstract
The Casimir force between electric and magnetic hyperbolic metamaterial slabs is investigated. Due to hyperbolic dispersion, the electromagnetic features of these metamaterials along the optical axis are different from those perpendicular to the optical axis; consequently, these features contribute differently to the Casimir effect. The repulsive Casimir force is formed between electric and magnetic hyperbolic metamaterial slabs; moreover, hyperbolic dispersion can enhance the repulsive effect. However, by utilizing the extremely anisotropic behavior of hyperbolic metamaterials and changing the separation distance between the two slabs, the restoring Casimir force emerges. Additionally, by considering the dispersion of both the permittivity and the permeability of hyperbolic metamaterials, the Casimir force reaches several equilibrium points at different separation distances. Furthermore, the Casimir force at room temperature is discussed. Although the temperature can weaken the effect of the restoring Casimir force, stable equilibria may remain upon choosing suitable filling factors. This work shows that hyperbolic metamaterials have potential applications in micro- and nanoelectromechanical systems, especially for maintaining stability and overcoming adhesion problems.
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Thiyam P, Parashar P, Shajesh KV, Malyi OI, Boström M, Milton KA, Brevik I, Persson C. Distance-Dependent Sign Reversal in the Casimir-Lifshitz Torque. PHYSICAL REVIEW LETTERS 2018; 120:131601. [PMID: 29694221 DOI: 10.1103/physrevlett.120.131601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Indexed: 06/08/2023]
Abstract
The Casimir-Lifshitz torque between two biaxially polarizable anisotropic planar slabs is shown to exhibit a nontrivial sign reversal in its rotational sense. The critical distance a_{c} between the slabs that marks this reversal is characterized by the frequency ω_{c}∼c/2a_{c} at which the in-planar polarizabilities along the two principal axes are equal. The two materials seek to align their principal axes of polarizabilities in one direction below a_{c}, while above a_{c} their axes try to align rotated perpendicular relative to their previous minimum energy orientation. The sign reversal disappears in the nonretarded limit. Our perturbative result, derived for the case when the differences in the relative polarizabilities are small, matches excellently with the exact theory for uniaxial materials. We illustrate our results for black phosphorus and phosphorene.
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Affiliation(s)
- Priyadarshini Thiyam
- Department of Materials Science and Engineering, Royal Institute of Technology, SE-100 44 Stockholm, Sweden
- Department of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Prachi Parashar
- Department of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - K V Shajesh
- Department of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
- Department of Physics, Southern Illinois University-Carbondale, Carbondale, Illinois 62901, USA
| | - Oleksandr I Malyi
- Centre for Materials Science and Nanotechnology, Department of Physics, University of Oslo, P.O. Box 1048 Blindern, NO-0316 Oslo, Norway
| | - Mathias Boström
- Department of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
- Centre for Materials Science and Nanotechnology, Department of Physics, University of Oslo, P.O. Box 1048 Blindern, NO-0316 Oslo, Norway
| | - Kimball A Milton
- Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Iver Brevik
- Department of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Clas Persson
- Department of Materials Science and Engineering, Royal Institute of Technology, SE-100 44 Stockholm, Sweden
- Centre for Materials Science and Nanotechnology, Department of Physics, University of Oslo, P.O. Box 1048 Blindern, NO-0316 Oslo, Norway
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Zhukovsky SV, Ozel T, Mutlugun E, Gaponik N, Eychmuller A, Lavrinenko AV, Demir HV, Gaponenko SV. Hyperbolic metamaterials based on quantum-dot plasmon-resonator nanocomposites. OPTICS EXPRESS 2014; 22:18290-18298. [PMID: 25089449 DOI: 10.1364/oe.22.018290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We theoretically demonstrate that nanocomposites made of colloidal semiconductor quantum dot monolayers placed between metal nanoparticle monolayers can function as multilayer hyperbolic metamaterials. Depending on the thickness of the spacer between the quantum dot and nanoparticle layers, the effective permittivity tensor of the nanocomposite is shown to become indefinite, resulting in increased photonic density of states and strong enhancement of quantum dot luminescence. This explains the results of recent experiments [T. Ozel et al., ACS Nano 5, 1328 (2011)] and confirms that hyperbolic metamaterials are capable of increasing the radiative decay rate of emission centers inside them. The proposed theoretical framework can also be used to design quantum-dot/nanoplasmonic composites with optimized luminescence enhancement.
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Noginov M, Lapine M, Podolskiy V, Kivshar Y. Focus issue: hyperbolic metamaterials. OPTICS EXPRESS 2013; 21:14895-14897. [PMID: 23787677 DOI: 10.1364/oe.21.014895] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
This special issue presents a cross-section of recent progress in the rapidly developing area of optics of hyperbolic metamaterials.
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Affiliation(s)
- Mikhail Noginov
- Department of Physics, Norfolk State University, Norfolk, VA, USA
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