In:
Journal of Optics, IOP Publishing, Vol. 24, No. 6 ( 2022-06-01), p. 065602-
Abstract:
In this work, it is theoretically and numerically demonstrated that an astigmatic transformation of a ν th-order edge dislocation (shaped as a zero-intensity straight line) of a coherent light field—where ν = n + α is a real positive number, n is integer, and 0 〈 α 〈 1 is fractional—produces n optical elliptic vortices (screw dislocations) with topological charge (TC) −1, which are arranged on a straight line perpendicular to the edge dislocation and found at Tricomi function zeros. We also reveal that at a distance from the said optical vortices (OV), an extra OV with charge −1 is born on the same straight line, which departs to the periphery with α tending to zero, or gets closer to the n OVs with α tending to 1. Additionally, we find that a countable number of OVs (intensity nulls) with charge −1 are produced at the field periphery and arranged on diverging hyperbolic curves equidistant from the straight line of the n main intensity nulls. These additional OVs, which we term as ‘escort’, either approach the beam center, accompanying the extra ‘companion’ OV if 0 〈 α 〈 0.5, or depart to the periphery, whereas the ‘companion’ keeps close to the main OVs if 0.5 〈 α 〈 1. At α =0 or α = 1, the ‘escort’ OVs are shown to be at infinity. At fractional ν , the TC of the whole optical beam is theoretically shown to be infinite. Numerical simulation results are in agreement with the theoretical findings.
Type of Medium:
Online Resource
ISSN:
2040-8978
,
2040-8986
DOI:
10.1088/2040-8986/ac69f7
Language:
Unknown
Publisher:
IOP Publishing
Publication Date:
2022
detail.hit.zdb_id:
2532144-4
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