scholarly journals Transverse intensity at the tight focus of a second-order cylindrical vector beam

2021 ◽  
Vol 45 (2) ◽  
pp. 165-171
Author(s):  
E.S. Kozlova ◽  
S.S. Stafeev ◽  
S.A. Fomchenkov ◽  
V.V. Podlipnov ◽  
V.V. Kotlyar
Keyword(s):  
Energy Flow ◽  
Light Field ◽  
Poynting Vector ◽  
Near Field ◽  
Fdtd Method ◽  
Optical Microscope ◽  
Second Order ◽  
Vector Beam ◽  
Tight Focus ◽  
Cylindrical Vector Beam

In this paper, an effect of a reverse energy flow at the focus of a second-order cylindrical vector beam which passed through amplitude zone plate was investigated with a scanning near-field optical microscope. A comparison of the intensity distribution detected with a pyramidal metallized cantilever with a hole and the characteristics of the light field calculated using a FDTD method and the Richards-Wolf formulas suggests that the cantilever is sensitive to the transverse intensity component rather than the total intensity or the components of the Poynting vector in the backflow region.

scholarly journals Formation of an elongated region of energy backflow using ring apertures

2019 ◽  
Vol 43 (2) ◽  
pp. 193-199
Author(s):  
S.S. Stafeev ◽  
V.V. Kotlyar
Keyword(s):  
Energy Flow ◽  
Poynting Vector ◽  
Numerical Aperture ◽  
Second Order ◽  
Depth Of Focus ◽  
Incident Wavelength ◽  
Entrance Pupil ◽  
High Numerical Aperture ◽  
Vector Beam ◽  
Cylindrical Vector Beam

In this paper, we have investigated the focusing of a second-order cylindrical vector beam by using a high numerical aperture (NA) lens limited by a ring aperture using the Richards-Wolf formulae. It was shown that the range of negative on-axis projections of the Poynting vector could be increased by increasing the depth of focus through the use of a ring aperture. It was shown that when focusing light with a lens with NA = 0.95, the use of a ring aperture limiting the entrance pupil angle to 0.9 of maximum, allows the depth of the region of negative on-axis Poynting vector projections to be four times increased, with the region width remaining almost unchanged and varying from 0.357 to 0.352 of the incident wavelength. Notably, the magnitude of the reverse energy flow was found to be larger than the direct one by a factor of 2.5.

scholarly journals Focusing a second-order cylindrical vector beam with a gradient index Mikaelian lens

2020 ◽  
Vol 44 (1) ◽  
pp. 29-33 ◽  
Author(s):  
S.S. Stafeev ◽  
E.S. Kozlova ◽  
A.G. Nalimov
Keyword(s):  
Free Space ◽  
Energy Flow ◽  
Second Order ◽  
Gradient Index ◽  
Vector Beam ◽  
Output Surface ◽  
Direct Energy ◽  
Lens Material ◽  
Cylindrical Vector Beam

In this paper, we numerically simulate the focusing of a second-order cylindrical vector beam with a gradient index Mikaelian lens. It is shown that the lens forms a region of the reverse energy flow near its output surface. If the lens has an on-axis micropit, the region of the direct energy flow can be confined within the lens material, whereas that of the reverse energy flow is put out in free space.

scholarly journals Tight focusing of second-order cylindrical vector beam by Mikaelian lens

2021 ◽  
Vol 1745 ◽  
pp. 012013
Author(s):  
S. S. Stafeev ◽  
E. S. Kozlova ◽  
A. G. Nalimov ◽  
V. V. Kotlyar
Keyword(s):  
Second Order ◽  
Vector Beam ◽  
Tight Focusing ◽  
Cylindrical Vector Beam

scholarly journals Energy flux of a vortex field focused using a secant gradient lens

2020 ◽  
Vol 44 (5) ◽  
pp. 707-711
Author(s):  
A.G. Nalimov
Keyword(s):  
Energy Flow ◽  
Poynting Vector ◽  
Second Order ◽  
Maximum Intensity ◽  
Gradient Index ◽  
Output Surface ◽  
Shadow Area ◽  
Vector Projection ◽  
Polarized Beam ◽  
Intensity Region

In this paper we simulated the focusing of left circular polarized beam with a second order phase vortex and a second-order cylindrical vector beam by a gradient index Mikaelian lens. It was shown numerically, that there is an area with a negative Poynting vector projection on Z axis, that can be called an area with backward energy flow. Using a cylindrical hole in the output surface of the lens and optimizing it one can obtain a negative flow, which will be situated in the maximum intensity region, unlike to previous papers, in which such backward energy flow regions were situated in a shadow area. Thereby, this lens will work as an “optical magnet”, it will attract Rayleigh particles (with diameter about 1/20 of the wavelength) to its surface.

scholarly journals High numerical aperture metalens to generate an energy backflow

2020 ◽  
Vol 44 (5) ◽  
pp. 691-698
Author(s):  
V.V. Kotlyar ◽  
S.S. Stafeev ◽  
L. O'Faolain ◽  
M.V. Kotlyar
Keyword(s):  
Focal Length ◽  
Ion Beam ◽  
Near Field ◽  
Fdtd Method ◽  
Numerical Aperture ◽  
Polarized Light ◽  
Optical Microscope ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Left Handed

Using electronic beam lithography and reactive ion beam etching, a metalens is manufactured in a thin layer of amorphous silicon of a 130-nm depth, a 30-µm diameter, and a 633-nm focal length (equal to the illumination wavelength). The metalens is composed of 16 sectored subwavelength binary gratings with a 220-nm period. The uniqueness of this metalens is that when illuminated by left-handed circularly polarized light, it is capable of generating a left-handed circularly polarized vortex beam with a topological charge of 2, generating a second-order cylindrical vector beam when illuminated by linearly polarized light. Both for linear and circular incident polarization, an energy backflow is found to be generated in the vicinity of the tight focus. Transverse intensity distributions measured with a scanning near-field optical microscope near the focus of the metalens are in qualitative agreement with the intensity distributions calculated by the FDTD method. This confirms that a backward energy flow takes place at the focus of the metalens. A metalens generating an energy backflow near its focus is fabricated and characterized for the first time.

A dual-functionality metalens to shape a circularly polarized optical vortex or a second-order cylindrical vector beam

2021 ◽  
Vol 43 ◽  
pp. 100898
Author(s):  
Victor V. Kotlyar ◽  
Sergey S. Stafeev ◽  
Anton G. Nalimov ◽  
Liam O’Faolain ◽  
Maria V. Kotlyar
Keyword(s):  
Optical Vortex ◽  
Second Order ◽  
Circularly Polarized ◽  
Vector Beam ◽  
Cylindrical Vector Beam
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