Sequence of focused optical vortices generated by a spiral fractal zone plate

A composite square zone plate (CSZP) is proposed to generate two two-arms-cross patterns with equal intensity and arbitrarily designed axial positions. Moreover, the CSZP with the spiral phase has two square optical vortices located at the arbitrary positions. In addition, we find that the same topological charge of twin square optical vortices for the CSZP follows a modulo-4 transmutation rule. The construction method of proposed zone plates is illustrated in detail. We prove numerically and experimentally that the CSZP and spiral-phase CSZP produce two tailorable two-arms-cross patterns with equal intensity and square optical vortices, respectively. The proposed zone plate can be used to generate hollow beams and have potential applications in infrared antennas and laser alignment systems.

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Comparison of the focused optical vortices produced by high-aperture phase conventional and spiral zone plates

Journal of Physics Conference Series ◽

10.1088/1742-6596/2103/1/012175 ◽

2021 ◽

Vol 2103 (1) ◽

pp. 012175

Author(s):

A A Savelyeva ◽

E S Kozlova ◽

V V Kotlyar

Keyword(s):

Gaussian Beam ◽

Focal Plane ◽

Topological Charge ◽

Focal Spot ◽

Zone Plate ◽

Fdtd Simulation ◽

Optical Vortices ◽

Phase Zone ◽

Linearly Polarized ◽

Sharp Focusing

Abstract Using the FDTD simulation, sharp focusing of a linearly polarized Gaussian beam with an embedded topological charge m = 3 by a phase zone plate and focusing of a Gaussian beam by a phase spiral zone plate with topological charge m = 3 were studied. The obtained results showed that proposed elements formed different patterns of intensity at a focal plane. The spiral zone plate forms a focal spot with three petals. At a distance of 13.5 μm from the focus, the lobe structure of the intensity (and energy flux) is replaced by an annular distribution.

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Investigation of the influence of amplitude spiral zone plate parameters on produced energy backflow

Computer Optics ◽

10.18287/2412-6179-2019-43-6-1093-1097 ◽

2019 ◽

Vol 43 (6) ◽

pp. 1093-1097

Author(s):

E.S. Kozlova

Keyword(s):

Time Domain ◽

Finite Difference Time Domain ◽

Energy Flow ◽

Optical Axis ◽

Longitudinal Component ◽

Zone Plate ◽

Optical Vortices ◽

Relief Height ◽

Vortex Beams ◽

Difference Time

Investigation of the influence of parameters of silver, aluminum, gold, and chromium spiral zone plates on the longitudinal component of Umov-Pointing vector in produced optical vortices by using the frequency-dependent finite-difference time-domain method is presented. It is shown that the aluminum spiral zone plate with a relief height of 50 nm gives an optical vortex with the smallest longitudinal component of Umov-Pointing vector on the optical axis. The gold spiral zone plate is the least effective for the formation of vortex beams with a reverse energy flow.

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