Tight focusing of the azimuthally polarized light beam for a sharper spot

Cheng, Zao; Zhou, Yiyu; Xia, Min; Li, Wei; Yang, Kecheng; Zhou, Yifeng

doi:10.1016/j.optlastec.2015.04.013

Cited by 14 publications

(16 citation statements)

References 25 publications

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“…For the azimuthally polarized vector modulated with the vortex 0-2π phase plate, the APBG with β = 0.5 is best, the APG with β = 0.5 is worst, and the APU is moderate. The result is the same to that in references [5, 12]. However, these phenomena cannot be preserved for other values of β .…”

supporting

confidence: 86%

“…Tight focusing of the kinds of polarized vector beams has aroused wide interests over the last decade due to its versatile properties, especially for unconventional polarization beams such as cylindrical vector [1-5] and hybrid polarization beams [6-8]. Radially and azimuthally polarized beams are two important types of cylindrical vector.…”

mentioning

confidence: 99%

“…To produce a tight circular focal spot from the azimuthally polarized beam, a vortex-0-2π-phase plate was employed to encode the beam and to make the interference constructive along each radial direction [5, 12, 13]. The resulted focal spot is circularly shaped and the electric field in the focal plane is mixed with circularly and elliptically polarized states.…”

mentioning

confidence: 99%

“…Most previous research [1-5, 9-15] only checked special values of β G and β BG , so the resulted conclusions are limited and many important focusing properties will be missed.…”

mentioning

confidence: 99%

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Generation of a controllable multifocal array from a modulated azimuthally polarized beam

Chen

Pacheco

et al. 2016

Opt. Lett.

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Comparisons of the focusing properties for the radially and azimuthally polarized beams with different pupil functions, such as uniform, Gaussian and Bessel-Gauss profiles, are presented. The results show that, for any pupil function, the spot sizes of the azimuthally polarized beam modulated with the vortex-0-2π-phase plate or the π-phase-step plate are smaller than that of the radially polarized beam encoded with or without these two types of plates. Then a type of multi-zone phase plate for generating tighter multifocal arrays from azimuthally polarized beams is proposed. The position and the linear polarization of the multifocal spots can be controlled by varying the pattern of the multi-zone phase plate and rotating the direction of the π-phase-step plate. In addition, for the radially polarized beam with Gaussian or Bessel-Gauss profiles and with the specified ratio of pupil diameter to beam diameter, the focal spot can be further reduced after modulated with the vortex-0-2π-phase plate, and the focal spot will be split into two after modulated with the π-phase-step plate. The latter property can be used to double the efficiency of parallel micro-manipulation.

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supporting

confidence: 86%

mentioning

confidence: 99%

mentioning

confidence: 99%

“…Most previous research [1-5, 9-15] only checked special values of β G and β BG , so the resulted conclusions are limited and many important focusing properties will be missed.…”

mentioning

confidence: 99%

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Generation of a controllable multifocal array from a modulated azimuthally polarized beam

Chen

Pacheco

et al. 2016

Opt. Lett.

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“…It has been numerically shown [1] that a Bessel-Gauss laser beam with azimuthal polarization having passed through a spiral phase plate (SPP) with the unit topological charge forms at the focus of a high-NA lens a subwavelength circular focal spot that is smaller in diameter than for radially polarized incident light. Using the Richards-Wolf formulas [2], it was also shown [1] that for an aplanatic spherical lens with NA = 1.4 (immersion with a refractive index of n = 1.518), for the azimuthal polarization and singular phase the focal spot size at half intensity was FWHM = 0.34λ, whereas radially polarized light produced the focal spot of size FWHM = 0.40λ in the same conditions, λ is the wavelength in vacuum [3]. However, no final formulas to describe the intensity of azimuthally polarized light, transmitted through an SPP, in the focus of the aplanatic lens were proposed in [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Tightly focused laser light with azimuthal polarization and singular phase

Kotlyar

Nalimov

2016

Computer Optics

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Using simplified Richards-Wolf formulas we show that laser light with azimuthal polarization and singular phase can produce a smaller focal spot than that from a laser beam with radial polarization, other conditions remaining the same. It is numerically shown that when focusing an azimuthally polarized laser beam with phase singularity using a zone plate a 1.3 times smaller focal spot can be attained than when an aplanatic lens is used. A spiral phase plate can be replaced with a phase step with a π-phase shift. In this case the subwavelength focal spot from a laser beam with azimuthal polarization, which is formed near the zone plate surface, loses circular symmetry, while becoming smaller and acquiring an elliptical form with radiuses of 0.273λ and 0.314λ (NA = 1).

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Optical Manipulation of Nanoparticles: A Selective Excitation Approach Using Highly Focused Orbital Angular Momentum Beams

Sadafi

Taghavi

Mota

et al. 2023

Advanced Photonics Research

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Orbital angular momentum and polarization states of highly focused vector vortex beams can be engineered to selectively excite the desired multipoles in nanoparticles, making them ideal candidates for complex optical applications. A platform based on the generalized Lorenz–Mie theory integrated with the complex source point method is developed to model the interaction of such beams with particles analytically. The existing platform is extended for obtaining the full‐vector electromagnetic fields, outlining the observed effects that adding a substrate brings to the problem space. Despite the cross‐coupling between different multipoles induced by the substrate, it is concluded that the proper choice of beam parameters enables the selective excitation of multipoles even in the critical case of a plasmonic substrate. The proposed formalism is general and allows a multipole study of the optical forces. Selective excitation is exploited to control the imparted optical forces on particles placed on a plasmonic substrate. 3D trapping regions are achievable for highly absorptive and high‐refractive‐index particles. Motion trajectory analyses are performed to demonstrate the trapping stability, concluding that highly focused optical beams, owing to the exceptional selective excitation ability, are suitable candidates for novel optical manipulation applications.

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Tight focusing of the azimuthally polarized light beam for a sharper spot

Cited by 14 publications

References 25 publications

Generation of a controllable multifocal array from a modulated azimuthally polarized beam

Generation of a controllable multifocal array from a modulated azimuthally polarized beam

Tightly focused laser light with azimuthal polarization and singular phase

Optical Manipulation of Nanoparticles: A Selective Excitation Approach Using Highly Focused Orbital Angular Momentum Beams

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