scholarly journals A simple analytical model of the angular momentum transformation in strongly focused light beams

Open Physics ◽  
2010 ◽  
Vol 8 (6) ◽  
Author(s):  
Aleksandr Bekshaev
Keyword(s):  
Angular Momentum ◽  
Cross Section ◽  
Field Distribution ◽  
Orbital Angular Momentum ◽  
Polarization State ◽  
Incident Beam ◽  
Quantitative Agreement ◽  
Beam Polarization ◽  
Circular Aperture ◽  
Analytical Results

AbstractA ray-optics model is proposed to describe the vector beam transformation in a strongly focusing optical system. In contrast to usual approaches based on the focused field distribution near the focal plane, we use the beam pattern formed immediately after the exit aperture. In this cross section, details of the output field distribution are of minor physical interest but proper allowance is made for transformation of the beam polarization state. This enables the spin and orbital angular momentum representations to be obtained, which are valid for any cross section of the transformed beam. Simple analytical results are available for a transversely homogeneous, circularly polarized incident beam confined by a circular aperture. Variations of the spin and orbital angular momenta of the output beam with change of the focusing strength are analyzed. The analytical results are in good qualitative and reasonable quantitative agreement with the results of numerical calculations performed for the Gaussian and Laguerre-Gaussian beams. The model supplies an efficient and physically transparent means for qualitative analysis of the spin-to-orbital angular momentum conversion. It can be generalized to incident beams with complex spatial and polarization structure.

Diffraction of Orbital Angular Momentum Carrying Optical Beams by a Circular Aperture

2013 ◽  
Author(s):  
Anindya Ambuj ◽  
S. Nomoto ◽  
Hsiao-harng Shiau ◽  
Reeta Vyas ◽  
Surendra Singh
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Circular Aperture ◽  
Optical Beams

Orbital angular momentum modes identification of optical vortices using binaural circular aperture

2019 ◽  
Vol 21 (6) ◽  
pp. 065603 ◽  
Author(s):  
Xueyu Chen ◽  
An Zhang ◽  
Junmin Liu ◽  
Zhiqiang Xie ◽  
Mingyang Su ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Optical Vortices ◽  
Circular Aperture

scholarly journals On-Chip Guiding of Higher-Order Orbital Angular Momentum Modes

Photonics ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 72 ◽  
Author(s):  
In Joon Lee ◽  
Sangin Kim
Keyword(s):  
Angular Momentum ◽  
Field Distribution ◽  
Orbital Angular Momentum ◽  
Rotational Symmetry ◽  
Higher Order ◽  
Waveguide Structure ◽  
Rotation Symmetry ◽  
Gaussian Mode ◽  
On Chip ◽  
Topological Charges

Higher-order orbital angular momentum (OAM) mode guiding in a waveguide which is suitable for on-chip integration has been investigated. Based on the relation between the Laguerre-Gaussian mode and the Hermite-Gaussian mode, it has been shown that two degenerate guided modes of π/2l-rotation symmetry can support the l-th order OAM mode. In order to mimic the rotational symmetry, we have proposed the waveguide structure of a cross-shaped core and designed a waveguide that can support OAM modes of ±1 and ±2 topological charges simultaneously at a wavelength of 1550 nm. Purity of the OAM modes guided in the designed waveguide has been assessed by numerically calculating their topological charges from the field distribution, which were close to the theoretical values. We also investigated the guiding of OAM modes of ±3 and ±4 topological charges in our proposed waveguide structure, which revealed the possibility of the separate guiding of those OAM modes with relatively lower purity.

scholarly journals Usability of Tilted Plasmon Antenna with Structured Light

Photonics ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 504
Author(s):  
Rafael Quintero-Torres ◽  
Jorge Luis Domínguez-Juárez ◽  
Mariia Shutova ◽  
Alexei V. Sokolov
Keyword(s):  
Angular Momentum ◽  
Numerical Simulations ◽  
Field Distribution ◽  
Orbital Angular Momentum ◽  
Near Field ◽  
Dielectric Surface ◽  
Antenna Design ◽  
Oblique Angle ◽  
Oblique Illumination ◽  
To Receive

We study the effect of oblique illumination on the functioning of a plasmonic nanoantenna for chiral light. The antenna is designed to receive a structured beam of light and produce a nanosized near-field distribution that possesses nonzero orbital angular momentum. The design consists of metal (gold) microrods laid on a dielectric surface and is compatible with well-developed nanofabrication techniques. Experimental arrangements often require such an antenna to operate in a tilted geometry, where input light is incident on the antenna at an oblique angle. We analyze the limitations that the angled illumination imposes and discuss approaches to mitigate these limitations. Through our numerical simulations, we find that tilt angles require modifications to the antenna design. Our analysis can guide current and future experimental configurations to push the limits of resolution and sensitivity.

scholarly journals Dielectric multi-momentum meta-transformer in the visible

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Lei Jin ◽  
Yao-Wei Huang ◽  
Zhongwei Jin ◽  
Robert C. Devlin ◽  
Zhaogang Dong ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Incident Beam ◽  
Information Storage ◽  
Intrinsic Properties ◽  
Optical Encryption ◽  
Phase Profile ◽  
Fixed Phase ◽  
Nanostructured Interfaces ◽  
Optical Integration

Abstract Metasurfaces as artificially nanostructured interfaces hold significant potential for multi-functionality, which may play a pivotal role in the next-generation compact nano-devices. The majority of multi-tasked metasurfaces encode or encrypt multi-information either into the carefully tailored metasurfaces or in pre-set complex incident beam arrays. Here, we propose and demonstrate a multi-momentum transformation metasurface (i.e., meta-transformer), by fully synergizing intrinsic properties of light, e.g., orbital angular momentum (OAM) and linear momentum (LM), with a fixed phase profile imparted by a metasurface. The OAM meta-transformer reconstructs different topologically charged beams into on-axis distinct patterns in the same plane. The LM meta-transformer converts red, green and blue illuminations to the on-axis images of “R”, “G” and “B” as well as vivid color holograms, respectively. Thanks to the infinite states of light-metasurface phase combinations, such ultra-compact meta-transformer has potential in information storage, nanophotonics, optical integration and optical encryption.

scholarly journals Usability of Tilted Plasmon Antenna with Structured Light

2021 ◽  
Author(s):  
Rafael Quintero-Torres ◽  
Jorge Luis Domínguez-Juárez ◽  
Mariia Shutova ◽  
Alexei V. Sokolov
Keyword(s):  
Angular Momentum ◽  
Numerical Simulations ◽  
Field Distribution ◽  
Orbital Angular Momentum ◽  
Near Field ◽  
Dielectric Surface ◽  
Antenna Design ◽  
Oblique Angle ◽  
Oblique Illumination ◽  
To Receive

We study the effect of oblique illumination on the functioning of a plasmonic nanoantenna for chiral light. The antenna is designed to receive a structured beam of light and produce a nanosized near-field distribution that possesses non-zero orbital angular momentum. The design consists of metal (gold) micro-rods laid on a dielectric surface and is compatible with well-developed nanofabrication techniques. Experimental arrangements often require such an antenna to operate in a tilted geometry, where input light is incident on the antenna at an oblique angle. We analyze the limitations that the angled illumination imposes and discuss approaches to mitigate these limitations. Through our numerical simulations, we find that tilt angles larger than 30 degrees require modifications to the antenna design. Our analysis guides current and future experimental configurations to pushing the limits of resolution and sensitivity.

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