Optical forces in coupled chiral particles

Wo, Kah Jen; Peng, Jie; Prasad, Madhava Krishna; Shi, Yuzhi; Li, Jensen; Wang, Shubo

doi:10.1103/physreva.102.043526

Cited by 12 publications

(8 citation statements)

References 43 publications

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“…We apply Eqs. ( 6) and (7) to analytically evaluate the absorption dissymmetry factor, and the result is shown in Fig. 3(c) as the solid line, which agrees well with the full-wave numerical result (symbol line).…”

Section: Absorption Of a Chiral Particle At The Type-i C Linesupporting

confidence: 81%

“…An object possesses chirality if it cannot be superimposed on its mirror image. A chiral particle and its mirror-imaged particle form a pair of enantiomers that can have dramatic different properties deriving from opposite chirality [2][3][4][5][6][7]. The detection/separation of different enantiomers, referred to as chiral discrimination, has long been a major interest due to important applications in various fields such as pharmaceutical industries [8,9].…”

Section: Introductionmentioning

confidence: 99%

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Chiral discrimination by polarization singularities of a metal sphere

Jia,

Peng,

Cheng

et al. 2021

Preprint

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The practical applications of chiral discrimination are usually limited by the weak chiral response of enantiomers and the high complexity of detection methods. Here, we propose to use the C lines (i.e., lines of polarization singularities) emerged in light scattering by a metal sphere to detect the chirality of small chiral particles. Using full-wave numerical simulations and analytical multipole expansions, we determined the absorption dissymmetry of the chiral particles at different positions on the C lines and found that it can be much larger than that induced by circularly polarized plane wave excitation. We uncover that the large dissymmetry factor is attributed to the asymmetric absorption of electric and magnetic dipoles induced by the C lines. The results can generate novel methods of chiral discrimination and may find applications in optical manipulations, optical sensing, and chiral quantum optics.

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Section: Absorption Of a Chiral Particle At The Type-i C Linesupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Chiral discrimination by polarization singularities of a metal sphere

Jia,

Peng,

Cheng

et al. 2021

Preprint

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“…It is made of gold with relative permittivity characterized by the Drude model ε Au = 1 − ω 2 p / ω 2 + iωω t , where ω p = 1.36 × 10 16 rad/s and ω t = 7.1 × 10 13 rad/s [52]. Such helices can be fabricated by using low-temperature shadow deposition [53] and have been extensively studied for its intriguing chiroptical properties, such as circular dichroism [54], optical forces [3,55,56], polarization conversion [57], and vortex beam generation [58]. We assume that the incident plane wave is linearly polarized with the electric field E inc = (− sin θê y + cos θê z )E 0 e (−ik0 cos θy−ik0 sin θz) , where θ is the incident angle between the wavevector k and − y direction and we have neglected the time-harmonic factor e −iωt .…”

Section: Mechanism and Realizationmentioning

confidence: 99%

Directional Dipole Dice Enabled by Anisotropic Chirality

Cheng¹,

Oyesina²,

Bo³

et al. 2022

Preprint

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Directional radiation and scattering play an essential role in light manipulation for various applications in integrated nanophotonics, antenna and metasurface designs, quantum optics, etc. The most elemental system with this property is the class of directional dipoles, including circular dipole, Huygens dipole, and Janus dipole. While each directional dipole has been realized in various optical structures, a mechanism that unifies all three directional dipoles in a single structure at the same frequency is missing. Here, we theoretically and experimentally demonstrate that the synergy of chirality and anisotropy can give rise to all three directional dipoles in one structure at the same frequency under linearly polarized plane wave excitations. This mechanism enables a simple helix particle to serve as a directional dipole dice (DDD), achieving selective manipulation of optical directionality via different "faces" of the particle. We employ three "faces" of the DDD to realize unidirectional excitation of guided waves with the directionality determined by the spin, the power flow, and the reactive power, respectively. This all-in-one realization of three directional dipoles can enable unprecedented control of both near-field and far-field directionality with broad applications in photonic integrated circuits, quantum information processing, and subwavelength-resolution imaging.

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“…Recently, optical pulling forces have stimulated intense interests in the fields of physics, mechanics, biology, and chemistry 1–13 . The pulling forces can be realized by using tractor beams or on various medium structures.…”

Section: Introductionmentioning

confidence: 99%

“…The pulling forces can be realized by using tractor beams or on various medium structures. Some effort has been devoted to studying negative optical forces on chiral structures 4–12 . Horai et al formulated an optical force under electronic resonance to enhance the optical force and realized the separation of nanometer‐sized chiral molecules 4 .…”

Section: Introductionmentioning

confidence: 99%

Radiation pressure on inhomogeneous active chiral structures with propagation matrix

Wang²,

Zhang

et al. 2022

Int J Numerical Modelling

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The propagation matrix method and the Maxwell stress tensor are developed to calculate radiation pressure on an inhomogeneous active chiral structure. Based on boundary conditions, a 4 Â 4 propagation matrix connecting two forward and two backward plane waves in adjacent chiral media is derived. This propagation matrix method allows us to access the net, co-and cross-polarized radiation pressure, which are expressed by coand cross-polarized reflection and transmission coefficients, exerted on magnetoelectric coupling inhomogeneous chiral slabs via the derivation of the Maxwell stress tensor for arbitrary polarized plane waves incidence. The accuracies of the methods are examined using the finite difference time domain method and the Lorentz force densities. The radiation pressure on a homogeneous or inhomogeneous active chiral slab affected by the angle of incidence, thickness, chirality parameter, and polarization states of incident waves are investigated. This work is believed to provide insights for detecting chirality parameters of inhomogeneous materials by optical forces.chiral, Maxwell stress tensor, optical forces, propagation matrix method, radiation | INTRODUCTIONRecently, optical pulling forces have stimulated intense interests in the fields of physics, mechanics, biology, and chemistry. [1][2][3][4][5][6][7][8][9][10][11][12][13] The pulling forces can be realized by using tractor beams or on various medium structures. Some effort has been devoted to studying negative optical forces on chiral structures. [4][5][6][7][8][9][10][11][12] Horai et al. formulated an optical force under electronic resonance to enhance the optical force and realized the separation of nanometer-sized chiral molecules. 4 Wo et al. investigated the optical forces induced by a plane wave on two chiral particles coupling with each other via evanescent near fields by using numerical and analytical methods. 12 Nevertheless, further studies on the complex mechanism of optical forces on inhomogeneous chiral structures are necessary.Chiral media can be classified into natural chiral medium, 14 artificial chiral structures, [15][16][17][18] and effective chiral medium. 19,20 Chiral structures with gain, instead of loss, are called active chiral structures. Though the majority of chiral media are passive, green fluorescent proteins, 14 active chiral metamaterials, 15 and chiral functional polymers, 16 and so forth, might be active chiral media. The Lorentz force density 21 and the Maxwell stress tensor, 22

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Optical forces in coupled chiral particles

Cited by 12 publications

References 43 publications

Chiral discrimination by polarization singularities of a metal sphere

Chiral discrimination by polarization singularities of a metal sphere

Directional Dipole Dice Enabled by Anisotropic Chirality

Radiation pressure on inhomogeneous active chiral structures with propagation matrix

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