scholarly journals Controlling near-field focusing of a mesoscale binary phase plate in an optical radiation field with circular polarization

2021 ◽  
Vol 45 (4) ◽  
pp. 512-519
Author(s):  
Y.E. Geints ◽  
O.V. Minin ◽  
E.K. Panina ◽  
I.V. Minin
Keyword(s):  
Focal Spot ◽  
Fresnel Zone ◽  
Near Field ◽  
Polarized Light ◽  
Minimum Size ◽  
Phase Plate ◽  
Focal Distance ◽  
Optical Wave ◽  
Circularly Polarized Light ◽  
Binary Phase

Binary Fresnel zone plates (ZP) are one of the most frequently used focusing elements of inplane optical schemes in micro- and nanophotonics. With a decrease in the diameter and focal distance of the ZP to meso-wavelength sizes, the parameters of the focusing region begin to be significantly influenced by features of the ZP design (material, thickness, relief depth). The spatial structure of the focal spot formed in the near-field is investigated by the numerical finite elements (FEM) simulations of the transmission of a plane optical wave through a mesoscale binary phase ZP. We show that there is a range of optimal etching depths of the ZP ridges and optimal thicknesses of the plate substrate, at which the best focusing of the incident optical wave is realized in terms of the maximum field intensity and the minimum size of the focal spot. In addition, a concept of a super-focusing binary phase ZP with an immersion layer in the form of a truncated cone fabricated of ZP material is proposed, which makes it possible to focus the circularly polarized light wave into a subdiffraction region with a half-width of about "lambda"/2n (n is the ZP refractive index).

scholarly journals Polarization Controllable Device for Simultaneous Generation of Surface Plasmon Polariton Bessel-Like Beams and Bottle Beams

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 975 ◽  
Author(s):  
Peizhen Qiu ◽  
Taiguo Lv ◽  
Yupei Zhang ◽  
Binbin Yu ◽  
Jiqing Lian ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Surface Plasmon Polariton ◽  
Near Field ◽  
Polarized Light ◽  
Simultaneous Generation ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Spatially Distributed ◽  
Potential Applications ◽  
Plasmon Polariton

Realizing multiple beam shaping functionalities in a single plasmonic device is crucial for photonic integration. Both plasmonic Bessel-like beams and bottle beams have potential applications in nanophotonics, particularly in plasmonic based circuits, near field optical trapping, and micro manipulation. Thus, it is very interesting to find new approaches for simultaneous generation of surface plasmon polariton Bessel-like beams and bottle beams in a single photonic device. Two types of polarization-dependent devices, which consist of arrays of spatially distributed sub-wavelength rectangular slits, are designed. The array of slits are specially arranged to construct an X-shaped or an IXI-shaped array, namely X-shaped device and IXI-shaped devices, respectively. Under illumination of circularly polarized light, plasmonic zero-order and first-order Bessel-like beams can be simultaneously generated on both sides of X-shaped devices. Plasmonic Bessel-like beam and bottle beam can be simultaneously generated on both sides of IXI-shaped devices. By changing the handedness of circularly polarized light, for both X-shaped and IXI-shaped devices, the positions of the generated plasmonic beams on either side of device can be dynamically interchanged.

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.

scholarly journals Spectral Engineering via Complex Patterns of Circular Nano-object Miniarrays: I. Convex Patterns Tunable by Integrated Lithography Realized by Circularly Polarized Light

Plasmonics ◽  
2020 ◽  
Author(s):  
Áron Sipos ◽  
Emese Tóth ◽  
Olivér A. Fekete ◽  
Mária Csete
Keyword(s):  
Near Field ◽  
Polarized Light ◽  
Localized Surface Plasmon ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Polarized Beams ◽  
Rectangular Pattern ◽  
Plasmon Resonances ◽  
Lift Off ◽  
Object Interactions

AbstractIllumination of colloid sphere monolayers by circularly polarized beams enables the fabrication of concave patterns composed of circular nanohole miniarrays that can be transferred into convex metal nano-object patterns via a lift-off procedure. Unique spectral and near-field properties are achievable by controlling the geometry of the central nanoring and quadrumer of slightly rotated satellite nanocrescents and by selecting those azimuthal orientations that promote localized plasmon resonances. The spectral and near-field effects of hexagonal patterns composed of uniform gold nanorings and nanocrescents, which can be prepared by transferring masks fabricated by a perpendicularly and obliquely incident single homogeneous circularly polarized beam, were studied to uncover the supported localized plasmonic modes. Artificial rectangular patterns composed of a singlet nanoring and singlet nanocrescent as well as quadrumer of four nanocrescents were investigated to analyze the effect of nano-object interactions and lattice type. It was proven that all nanophotonical phenomena are governed by the azimuthal orientation independent localized resonance on the nanorings and by the C2, C1, and U resonances on the nanocrescents in case of $\bar {E}$ Ē -field direction perpendicular and parallel to their symmetry axes. The interaction between localized surface plasmon resonances on individual nano-objects is weak, whereas scattered photonic modes have a perturbative role at the Rayleigh anomaly only on the larger periodic rectangular pattern of miniarrays. Considerable fluorescence enhancement of dipolar emitters is achievable at spectral locations promoting the C and U resonances on the constituent nano-object.

scholarly journals The investigation of the features of focusing vortex super-Gaussian beams with a variable-height diffractive axicon

2021 ◽  
Vol 45 (2) ◽  
pp. 214-221
Author(s):  
D.A. Savelyev
Keyword(s):  
Gaussian Beam ◽  
Circular Polarization ◽  
Focal Spot ◽  
Near Field ◽  
Optical Element ◽  
Spot Size ◽  
Minimum Size ◽  
Focal Spot Size ◽  
Diffractive Axicon ◽  
Difference Time

Spatial intensity distributions of the Laguerre-superGauss modes (1,0) as well as a super-Gaussian beam with radial and circular polarization were investigated versus changes in the height of a diffractive axicon. The height of the relief of the optical element varied from 0.25λ to 3λ. The modeling by a finite-difference time-domain method showed that variations in the height of the diffractive axicon significantly affect the diffraction pattern in the near field of the axicon. The smallest focal spot size for a super-Gaussian beam was obtained for radial polarization at a height equal to two wavelengths. The minimum size of the focal spot for the Laguerre-superGauss mode (1,0) was obtained for circular "–" polarization with an element height equal to a quarter of the wavelength.

scholarly journals Emission of circularly polarized light by a linear dipole

2019 ◽  
Vol 5 (6) ◽  
pp. eaav7588 ◽  
Author(s):  
Martin Neugebauer ◽  
Peter Banzer ◽  
Sergey Nechayev
Keyword(s):  
Near Field ◽  
Polarization State ◽  
Polarized Light ◽  
Angular Spectrum ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Nanophotonic Devices ◽  
On Chip ◽  
The Individual ◽  
Linear Dipole

Controlling the polarization state and the propagation direction of photons is a fundamental prerequisite for many nanophotonic devices and a precursor for future on-chip communication, where the emission properties of individual emitters are particularly relevant. Here, we report on the emission of partially circularly polarized photons by a linear dipole. The underlying effect is linked to the near-field part of the angular spectrum of the dipole, and it occurs in any type of linear dipole emitter, ranging from atoms and quantum dots to molecules and dipole-like antennas. We experimentally observe it by near-field to far-field transformation at a planar dielectric interface and numerically demonstrate the utility of this phenomenon by coupling the circularly polarized light to the individual paths of crossing waveguides.

scholarly journals Tight focusing of circularly polarized light limited by semicircular aperture

2021 ◽  
Vol 2103 (1) ◽  
pp. 012164
Author(s):  
V D Zaitsev ◽  
S S Stafeev ◽  
V V Kotlyar
Keyword(s):  
Focal Spot ◽  
Reverse Flow ◽  
Polarization State ◽  
Azimuthal Angle ◽  
Numerical Aperture ◽  
Polarized Light ◽  
Flow Region ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Direction Of Polarization

Abstract In this work, the focusing of a circularly polarized plane wave (wavelength 532 nm) was simulated by a lens with a numerical aperture NA = 0.95. The wave front was considered flat. When integrating according to the Richards-Wolf formulas, the semicircular aperture was set by limiting the azimuthal angle from 0 to π. It was shown that when focusing light with right and left circular polarization, the focal spot turns out to be elliptical - elongated along the y axis, and, depending on the direction of polarization, its center shifts by about 0.05 μm in different directions along the x axis. It was also shown that the reverse flow region is located near the focal spot (at a distance of 0.25 μm from the center). Depending on the direction of polarization, it is located either to the right or to the left of the focal spot. Thus, the polarization state of the incident radiation can be determined from the displacement of the spot in focus.

scholarly journals Spectral Engineering Via Complex Patterns of Circular Nano-Object Miniarrays: II. Concave Patterns Tunable by Integrated Lithography Realized by Circularly Polarized Light

Plasmonics ◽  
2020 ◽  
Author(s):  
Emese Tóth ◽  
Áron Sipos ◽  
Olivér A. Fekete ◽  
Mária Csete
Keyword(s):  
Spectral Response ◽  
Near Field ◽  
Azimuthal Angle ◽  
Polarized Light ◽  
Geometrical Parameters ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Rectangular Pattern ◽  
Beam Incident ◽  
Potential Applications

AbstractThe use of circularly polarized beams in interferometric illumination of colloid sphere monolayers enables the direct fabrication of rectangular patterns composed of circular nanohole miniarrays in metal films. This paper presents a study on the spectral and near-field effects of complex rectangular patterns consisted of a central nanoring and slightly rotated satellite nanocrescents in azimuthal orientations, which promote coupling between localized and propagating plasmons. To inspect the localized modes separately, we investigate the spectral responses and near-field phenomena of hexagonal patterns composed of uniform nanorings and nanocrescents, which can be fabricated by a single, homogeneous, circularly polarized beam incident perpendicularly and obliquely, respectively. To understand the interaction of localized and propagating modes, we analyze artificial rectangular patterns composed of a singlet nanoring, a singlet horizontal nanocrescent, and a quadrumer of four slightly rotated nanocrescents. The results demonstrate that on the rectangular pattern of a singlet horizontal nanocrescent the interacting C2 and C1 localized resonances in the C orientation ($$0^{\circ }$$ 0 ∘ azimuthal angle) and the U localized resonance coupled with propagating surface plasmon polaritons (SPPs) in the U orientation ($$90^{\circ }$$ 90 ∘ azimuthal angle) manifest themselves in similar split spectra. Moreover, split spectra appear due to the coupling of the azimuthal orientation independent localized resonance on the nanorings and the SPPs propagating on their rectangular pattern in the U orientation. The spectral response of the complex miniarray pattern can be precisely tuned by varying the geometrical parameters of the moderately interacting nanoholes and the pattern period. In appropriate configurations, the fluorescence of the dipolar emitters is enhanced, which has potential applications in bio-object detection.

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