Generation of V-point polarization singularity array by Dammann gratings

Desai, Jawahar; Gangwar, Kapil K.; Ruchi, Ruchi; Khare, Kedar; Senthilkumaran, P.

doi:10.1007/s00340-022-07830-x

Cited by 4 publications

(2 citation statements)

References 59 publications

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“…In addition, a lot of works studied sharp focusing of CVBs of the first order [5,6], of the high order [7,8], of the fractional order [9], as well as focusing of the vortex beams with high-order azimuthal polarization [10]. There are a lot of different ways to generate cylindrical vector beams by using, for instance, Twyman Green interferometer [11], Dammann gratings [12], metasurface [13,14], spatial light modulator [15], or elements fabricated by digital laser printing [16,17].…”

Section: Introductionmentioning

confidence: 99%

Spin Hall Effect before and after the Focus of a High-Order Cylindrical Vector Beam

et al. 2022

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It is known that in the cross-section of a high-order cylindrical vector beam (CVB), polarization is locally linear. The higher the beam order, the higher the number of full rotations of the vector of local linear polarization when passing along a contour around the optical axis. It is also known that both in the input and in the focal planes, the CVB has neither the spin angular momentum (SAM), nor the orbital angular momentum (OAM). We demonstrate here that near the focal plane of the CVB (before and after the focus), an even number of local subwavelength areas is generated, where the polarization vector in each point is rotating. In addition, in the neighboring areas, polarization vectors are rotating in different directions, so that the longitudinal component of SAM vectors in these neighboring areas is of the opposite sign. In addition, after the beam passes the focus, the rotation direction of the polarization vector in each point of the beam cross-section is changed to the opposite one. Such spatial separation of the left and right rotation of the polarization vectors manifests so that the optical spin Hall effect takes place.

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Section: Introductionmentioning

confidence: 99%

Spin Hall Effect before and after the Focus of a High-Order Cylindrical Vector Beam

et al. 2022

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“…These cold spots have been identified in the near-field of nanoparticles 6 and individual spots may be controllably displaced by superposing plane waves 7 . Lattices of points with vanishing intensity in a vector polarization field have also been generated in the transverse plane 8 , 9 . Here, we seek a method for deterministically placing multiple 0D singularities that is not bound to periodic spacing and does not mandate the use of multiple beams.…”

Section: Introductionmentioning

confidence: 99%

Point singularity array with metasurfaces

et al. 2023

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Phase singularities are loci of darkness surrounded by monochromatic light in a scalar field, with applications in optical trapping, super-resolution imaging, and structured light-matter interactions. Although 1D singular structures, like optical vortices, are common due to their robust topological properties, uncommon 0D (point) and 2D (sheet) singularities can be generated by wavefront-shaping devices like metasurfaces. With the design flexibility of metasurfaces, we deterministically position ten identical point singularities using a single illumination source. The phasefront is inverse-designed using phase-gradient maximization with an automatically-differentiable propagator and produces tight longitudinal intensity confinement. The array is experimentally realized with a TiO2 metasurface. One possible application is blue-detuned neutral atom trap arrays, for which this field would enforce 3D confinement and a potential depth around 0.22 mK per watt of incident laser power. We show that metasurface-enabled point singularity engineering may significantly simplify and miniaturize the optical architecture for super-resolution microscopes and dark traps.

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