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Ren X, Zeng X, Liu C, Cheng C, Zhang R, Zhang Y, Zhan Z, Kong Q, Sun R, Cheng C. Optical Spin Hall Effect in Closed Elliptical Plasmonic Nanoslit with Noncircular Symmetry. NANOMATERIALS 2021; 11:nano11040851. [PMID: 33810485 PMCID: PMC8066872 DOI: 10.3390/nano11040851] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/21/2021] [Accepted: 03/22/2021] [Indexed: 01/13/2023]
Abstract
We investigated the optical spin Hall effect (OSHE) of the light field from a closed elliptical metallic curvilinear nanoslit instead of the usual truncated curvilinear nanoslit. By making use of the characteristic bright spots in the light field formed by the noncircular symmetry of the elliptical slit and by introducing a method to separate the incident spin component (ISC) and converted spin component (CSC) of the output field, the OSHE manifested in the spot shifts in the CSC was more clearly observable and easily measurable. The slope of the elliptical slit, which was inverse along the principal axes, provided a geometric phase gradient to yield the opposite shifts of the characteristic spots in centrosymmetry, with a double shift achieved between the spots. Regarding the mechanism of this phenomenon, the flip of the spin angular momentum (SAM) of CSC gave rise to an extrinsic orbital angular momentum corresponding to the shifts of the wavelet profiles of slit elements in the same rotational direction to satisfy the conservation law. The analytical calculation and simulation of finite-difference time domain were performed for both the slit element and the whole slit ellipse, and the evolutions of the spot shifts as well as the underlying OSHE with the parameters of the ellipse were achieved. Experimental demonstrations were conducted and had consistent results. This study could be of great significance for subjects related to the applications of the OSHE.
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Affiliation(s)
- Xiaorong Ren
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, China; (X.R.); (X.Z.); (C.L.); (R.Z.); (Y.Z.); (Z.Z.); (Q.K.); (R.S.)
- School of Electronic and Information Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
| | - Xiangyu Zeng
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, China; (X.R.); (X.Z.); (C.L.); (R.Z.); (Y.Z.); (Z.Z.); (Q.K.); (R.S.)
| | - Chunxiang Liu
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, China; (X.R.); (X.Z.); (C.L.); (R.Z.); (Y.Z.); (Z.Z.); (Q.K.); (R.S.)
| | - Chuanfu Cheng
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, China; (X.R.); (X.Z.); (C.L.); (R.Z.); (Y.Z.); (Z.Z.); (Q.K.); (R.S.)
- Correspondence: (C.C.); (C.C.)
| | - Ruirui Zhang
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, China; (X.R.); (X.Z.); (C.L.); (R.Z.); (Y.Z.); (Z.Z.); (Q.K.); (R.S.)
| | - Yuqin Zhang
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, China; (X.R.); (X.Z.); (C.L.); (R.Z.); (Y.Z.); (Z.Z.); (Q.K.); (R.S.)
| | - Zijun Zhan
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, China; (X.R.); (X.Z.); (C.L.); (R.Z.); (Y.Z.); (Z.Z.); (Q.K.); (R.S.)
| | - Qian Kong
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, China; (X.R.); (X.Z.); (C.L.); (R.Z.); (Y.Z.); (Z.Z.); (Q.K.); (R.S.)
| | - Rui Sun
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, China; (X.R.); (X.Z.); (C.L.); (R.Z.); (Y.Z.); (Z.Z.); (Q.K.); (R.S.)
| | - Chen Cheng
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, China; (X.R.); (X.Z.); (C.L.); (R.Z.); (Y.Z.); (Z.Z.); (Q.K.); (R.S.)
- Correspondence: (C.C.); (C.C.)
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Litvin IA, Mueller NS, Reich S. Selective excitation of localized surface plasmons by structured light. OPTICS EXPRESS 2020; 28:24262-24274. [PMID: 32752408 DOI: 10.1364/oe.399225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 07/14/2020] [Indexed: 06/11/2023]
Abstract
We investigated the selective excitation of localized surface plasmons by structured light. We derive selection rules using group theory and propose a fitting integral to quantify the contribution of the eigenmodes to the absorption spectra. Based on the result we investigate three nano oligomers of different symmetry (trimer, quadrumer, and hexamer) in detail using finite-difference time-domain simulations. We show that by controlling the incident light polarization and phase pattern we are able to control the absorption and scattering spectra. Additionally, we demonstrate that the fitting between the incident light and the oligomer modes may favor a number of modes to oscillate. Dark modes produce strong changes in the absorption spectrum and bright modes in the scattering spectrum. The experimental precision (axial shift error) may be on the same order as the oligomer diameter making the orbital angular momentum selection rules robust enough for experimental observation.
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Shi R, Gao DL, Hu H, Wang YQ, Gao L. Enhanced broadband spin Hall effects by core-shell nanoparticles. OPTICS EXPRESS 2019; 27:4808-4817. [PMID: 30876091 DOI: 10.1364/oe.27.004808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 02/02/2019] [Indexed: 06/09/2023]
Abstract
Spin-orbit interaction of light is ubiquitous in any optical system. However, the relevant spin Hall effects are usually weak for the light scattering from nanoparticles, making it challengeable to detect directly in experiment. In this paper, we demonstrate enhanced broadband spin Hall effects by using core-shell nanoparticles. The electric and magnetic dipoles can be tuned by the core-shell nanostructure with great freedom, and are excited simultaneously in a broadband spectrum, resulting in robust enhanced spin Hall shifts. Moreover, the coupling of the electric dipole and electric quadrupole gives rise to enhanced spin Hall shifts at both forward and backward directions. Numerical results from far-field and near-field verify the strong spin-orbit interaction of light. Our work offers a new way to exploit spin Hall effects in superresolution imaging and spin-dependent displacement sensing.
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