Topological charge of two parallel Laguerre-Gaussian beams

Kotlyar, V. V.; Kovalev, A. A.; Amiri, Pouria; Soltani, Peyman; Rasouli, Saifollah

doi:10.1364/oe.446743

Cited by 9 publications

(4 citation statements)

References 18 publications

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“…So, the diffraction pattern of the output probe field can be manipulated by the magnitude and sign of the OAM of the coupling LG field whenever an external gate voltage is applied to the QDM medium. Our numerical findings reveal that by employing a linear superposition of two Laguerre–Gaussian (LG) modes with opposite helical wavefronts for the coupling field 41 , 42 , a more intricate Fresnel diffraction pattern devoid of deflection emerges. It is noteworthy that the deflections of the two opposite helical LG beams occur in opposing directions.…”

Section: Resultsmentioning

confidence: 96%

Voltage-controlled two-dimensional Fresnel diffraction pattern in quantum dot molecules

Mehrabzadeh,

Khoshdel,

Mahmoudi

et al. 2024

Sci Rep

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This study explores the influence of inter-dot tunneling effects within a quantum dot molecule on the Fresnel diffraction phenomenon. Our findings indicate that the Fresnel diffraction of the output probe Gaussian field can be manipulated by adjusting the inter-dot tunneling parameter’s strength and the characteristics of the coupling field. The inter-dot tunneling effect establishes a closed-loop system, setting conditions for the interference of the applied fields. We specifically examine a Laguerre–Gaussian (LG) coupling field, investigating how its properties-such as strength, value, and sign of the orbital angular momentum (OAM)-impact the Fresnel diffraction of the output probe field. Increasing the inter-dot tunneling parameter and the coupling LG field’s strength allows for control over the spatial distribution of the Fresnel diffraction pattern. Notably, the inter-dot tunneling parameter can disturb the symmetry of the diffraction patterns. Additionally, considering a negative OAM for the coupling LG field transforms the diffraction pattern into its inverse shape. This suggests that, in the presence of the inter-dot tunneling effect, the Fresnel diffraction pattern is contingent on the direction of rotation of the helical phase front of the coupling LG field. Our results offer insights into quantum control of Fresnel diffraction patterns and the identification of OAM in LG beams, presenting potential applications in quantum technologies.

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Section: Resultsmentioning

confidence: 96%

Voltage-controlled two-dimensional Fresnel diffraction pattern in quantum dot molecules

Mehrabzadeh,

Khoshdel,

Mahmoudi

et al. 2024

Sci Rep

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“…Some of these unsolved problems are related to the important quantity of the optical vortices, their topological charge (TC) [1], although, due to its discreteness, it demonstrates a significant stability when coherent vortex beams propagate in turbulence [2][3][4] and can be used for identifying incoming optical signals. For instance, it was only recently discovered [5] that the TC of a superposition of two parallel, monochromatic Laguerre-Gaussian (LG) beams with their azimuthal indices of different parity can be different depending on which of these two beams is on the left and which is on the right. If these beams are swapped in the superposition, their common TC changes by 1.…”

Section: Introductionmentioning

confidence: 99%

Topological Charge of Multi-Color Optical Vortices

et al. 2022

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The topological charge of an optical vortex is a quantity rather stable against phase distortions, for example, turbulence. This makes the topological charge attractive for optical communications, but for many structured beams it is unknown. Here, we derive the topological charge (TC) of a coaxial superposition of spatially coherent Laguerre–Gaussian beams with different colors, each beam with its own wavelength and its own TC. It turns out that the TC of such a superposition equals the TC of the LG beam with a longer wavelength, regardless of the weight coefficient of this beam in the superposition and regardless of its TC. It is interesting that the instantaneous TC of such a superposition is conserved on propagation, whereas the time-averaged intensity distribution of the colored optical vortex changes its gamut; if, in the near field, the colors of the light rings arrange along the radius according to their TCs in the superposition from lower to greater, then, on space propagation, the colors of the light rings in the cross-section are arranged in reverse order from the greater TC to the lower TC. We also demonstrate that, by choosing appropriate wavelengths (blue, green, and red) in a three-color superposition of single-ringed LG beams, it is possible to generate, at some propagation distance, a time-averaged light ring of the white color. If all the beams in a three-color superposition of single-ringed LG beams have the same TC, then there is a single ring of nearly white light in the initial plane. Then, on propagation in space, light rings of different colors acquire different radii: a smaller ring radius for a shorter wavelength.

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“…И некоторые из этих нерешенных вопросов связаны с такой важной характеристикой оптических вихрей, как топологический заряд (ТЗ) [1]. Например, только недавно было показано [2], что ТЗ суперпозиции двух параллельных пучков Лагерра-Гаусса (ЛГ) с азимутальными номерами разной четности разный, в зависимости от того, кто в этой «паре» слева, а кто справа. Если пучки в суперпозиции переставить местами, то ТЗ изменится на 1.…”

Section: Introductionunclassified

Coherent superposition of the Laguerre-Gaussian beams with different wavelengths: colored optical vortices

Kotlyar¹,

Kovalev²,

Savelyeva³

2022

Computer Optics

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We calculate the topological charge (TC) of a coherent axial superposition of different-"color" Laguerre-Gaussian (LG) beams, each having a different wavelength and TC. It is found that the TC of such a superposition is equal to the TC of the longer-wavelength constituent LG beam regardless of the weight coefficient of this beam in the superposition and its corresponding TC. It is interesting that the instantaneous TC of such a superposition is conserved and the (time-averaged) intensity distribution of the "colored" optical vortex changes its light "gamut": whereas in the near field with increasing radius, colors of the light rings (rainbow) change according to their TC in the superposition from the smaller TC to the larger one, upon free-space propagation (to the far field), with increasing radius, the ring colors in the rainbow get arranged in the reverse order from the larger TC to the smaller one. It is also shown that choosing the wavelengths (blue, green, and red)in a special way in a three-color superposition of single-ringed LG beams allows obtaining a time-averaged white light ring at a certain distance.

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Topological charge of two parallel Laguerre-Gaussian beams

Cited by 9 publications

References 18 publications

Voltage-controlled two-dimensional Fresnel diffraction pattern in quantum dot molecules

Voltage-controlled two-dimensional Fresnel diffraction pattern in quantum dot molecules

Topological Charge of Multi-Color Optical Vortices

Coherent superposition of the Laguerre-Gaussian beams with different wavelengths: colored optical vortices

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