Displacements of optical vortices in Laguerre–Gaussian beams diffracted by a soft-edge screen

Bekshaev, A. Ya.; Mikhaylovskaya, Lidiya

doi:10.1016/j.optcom.2019.04.085

Cited by 6 publications

(8 citation statements)

References 30 publications

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“…General features of the incident beam transformation are illustrated by figure 1 (see [14][15][16][17][18].). The incident monochromatic paraxial beam propagates along axis z.…”

Section: Description Of the Ov Phase-step Diffractionmentioning

confidence: 99%

“…Among multiple fascinating physical effects associated with optical vortices (OVs) [1][2][3][4], the most impressive ones accompany the usual edge-diffraction phenomena [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Many aspects of the diffracted beam behavior expressively demonstrate the inherent OV properties, in particular, its helical nature and the transverse energy circulation, due to which the diffracted beam intensity profile effectively 'rotates' during the post-screen propagation [4,9,11,12].…”

Section: Introductionmentioning

confidence: 99%

“…An incident circular OV with non-unity topological charge [1][2][3] m is decomposed into a set of |m| single-charged 'secondary' singularities which form an intricate 'singular skeleton' [3,16,18] of the diffracted beam. The secondary OVs evolve separately along complex spiral-like 3D trajectories which contain additional oscillations, pulsations and sometimes 'backward' segments [16,18]; when the beam structure is observed in a given cross section, such 'bendings' of the OV trajectory look as topological reactions [3,[15][16][17][18] with generation of 'new' OVs and annihilation of 'old' ones. The similar spiral-like migration of the OVs can be seen in a fixed diffracted-beam cross section when the screen edge translates across the incident beam profile (a-dependent evolution [16]).…”

Section: Introductionmentioning

confidence: 99%

“…The similar spiral-like migration of the OVs can be seen in a fixed diffracted-beam cross section when the screen edge translates across the incident beam profile (a-dependent evolution [16]). In a whole, the singular skeleton of the diffracted beam forms a well-developed and controllable set of OVs with the potential of being fruitfully applied in sensitive metrology, optical diagnostics and optical-trapping techniques [14][15][16][17][18][19][20][21][22][23]. In the latter case, not only the OV positions but also its morphology parametersthe orientation and form-factor of an equal-intensity ellipse in the nearest vicinity of the OV core (isolated amplitude zero) within the diffracted beam cross section [24][25][26][27]-are important and should be controlled.…”

Section: Introductionmentioning

confidence: 99%

“…Additional possibilities for the purposeful formation of controllable singular skeletons arise when the diffraction obstacle is not an opaque screen with a sharp or smooth [17] edge but is formed by two (semi)transparent areas divided by a rectilinear boundary [18] (see figure 1). Especially, the pure-phase diffractive elements with rectilinear phase step (the amplitude transmission is homogeneous but a certain constant phase shift φ is introduced between two abovementioned areas of the transmitted beam cross section) offer many advantages in diagnostic and technological applications [19,20,[28][29][30].…”

Section: Introductionmentioning

confidence: 99%

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Controllable singular skeleton formation by means of the Kummer optical-vortex diffraction at a rectilinear phase step

Bekshaev¹,

Chernykh²,

Khoroshun³

et al. 2021

J. Opt.

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We study positions and morphology of optical vortices (OVs) within the field obtained after transmitting a circular single-charged OV-beam through the transparent screen with a rectilinear π-phase step. Experimental results are obtained with the help of a programmable spatial light modulator which is used for the Kummer beam formation and for introduction of the π-step phase difference at a desirable position within the incident beam cross section. The theory based on the Kirchhoff–Fresnel approximation shows a good agreement with the experimental data; peculiar features of the Kummer beam diffraction are elucidated in the course of confrontation against the results involving the Laguerre–Gaussian beam model with the same transverse size and spherical wavefront component. The diffracted field contains a system of interacting OVs (singular skeleton) which demonstrate a regular evolution (migration) within the diffracted beam cross section while the π-phase step translates across the incident beam; depending on the step position, new OV pairs may emerge and/or annihilate in the topological reactions. The morphology parameters of the separate diffracted-field OVs (orientations and form-factors of the near-core equal-intensity ellipses) also depend on the stage of the OV evolution and indicate conditions favorable for the efficient trapping and guiding of microparticles. The results may be useful for the diagnostics of OVs, experimental measurements of phase objects and in micromanipulation techniques.

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“…General features of the incident beam transformation are illustrated by figure 1 (see [14][15][16][17][18].). The incident monochromatic paraxial beam propagates along axis z.…”

Section: Description Of the Ov Phase-step Diffractionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Controllable singular skeleton formation by means of the Kummer optical-vortex diffraction at a rectilinear phase step

Bekshaev¹,

Chernykh²,

Khoroshun³

et al. 2021

J. Opt.

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Geometric spin Hall effect and polarization-dependent transformations in the oblique section of a paraxial light beam

Bekshaev

Ternovsky

2023

Phys. Scr.

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The spatial structure of light beams is usually considered in the transverse cross sections but supplementary analysis of the field pattern across an oblique plane may disclose additional details of the internal beam structure and energy flow distributions. Their manifestations are known as “geometric spin Hall effect of light” (gSHEL). We analyze the “practical” gSHEL scheme in which the light energy distribution is registered by a detector whose input plane is inclined with respect to the propagation axis. Based on the vector beam model and using the formalism of optical Wigner matrices, we find that the oblique-plane energy distribution differs from that observed in the transverse cross section. This difference is associated with the azimuthal energy circulation and the orbital angular momentum (AM) of the beam; it can be expressed as the lateral shift of the mean-weighted beam position (beam centroid). The similar effect can be observed in elliptically polarized beams without orbital AM: there, the oblique-section projection reveals a specific asymmetry induced by the spin AM in the longitudinal field components of such beams. The polarization-induced oblique-section beam shift is rather weak in paraxial approximation but can be observable if the light-detecting procedure is selectively sensitive to the longitudinal optical-field component.

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Airy transform of Laguerre-Gaussian beams

Zhou¹,

Wang²,

Feng³

2020

Opt. Express

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Airy transform of Laguerre-Gaussian (LG) beams is investigated. As typical examples, the analytic expressions for the Airy transform of LG01, LG02, LG11, and LG12 modes are derived, which are special optical beams including the Airy and Airyprime functions. Based on these analytical expressions, the Airy transform of LG01, LG02, LG11, and LG12 modes are numerically and experimentally investigated, respectively. The effects of the control parameters α and β on the normalized intensity distribution of a Laguerre-Gaussian beam passing through Airy transform optical systems are investigated, respectively. It is found that the signs of the control parameters only affect the location of the beam spot, while the sizes of the control parameters will affect the characteristics of the beam spot. When the absolute values of the control parameters α and β decrease, the number of the side lobes in the beam spot, the beam spot size, and the Airy feature decrease, while the Laguerre-Gaussian characteristic is strengthened. By altering the control parameters α and β, the performance of these special optical beams is diversified. The experimental results are consistent with the theoretical simulations. The Airy transform of other Laguerre-Gaussian beams can be investigated in the same way. The properties of the Airy transform of Laguerre-Gaussian beams are well demonstrated. This research provides another approach to obtain special optical beams and expands the application of Laguerre-Gaussian beams.

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Displacements of optical vortices in Laguerre–Gaussian beams diffracted by a soft-edge screen

Cited by 6 publications

References 30 publications

Controllable singular skeleton formation by means of the Kummer optical-vortex diffraction at a rectilinear phase step

Controllable singular skeleton formation by means of the Kummer optical-vortex diffraction at a rectilinear phase step

Geometric spin Hall effect and polarization-dependent transformations in the oblique section of a paraxial light beam

Airy transform of Laguerre-Gaussian beams

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