Arbitrary spin-to–orbital angular momentum conversion of light

Science ◽  
2017 ◽  
Vol 358 (6365) ◽  
pp. 896-901 ◽  
Author(s):  
Robert C. Devlin ◽  
Antonio Ambrosio ◽  
Noah A. Rubin ◽  
J. P. Balthasar Mueller ◽  
Federico Capasso
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Optical Communication ◽  
Arbitrary Spin ◽  
Spin States ◽  
Spin Angular Momentum ◽  
Optical Elements ◽  
Left And Right ◽  
General Material ◽  
Elliptically Polarized

Optical elements that convert the spin angular momentum (SAM) of light into vortex beams have found applications in classical and quantum optics. These elements—SAM-to–orbital angular momentum (OAM) converters—are based on the geometric phase and only permit the conversion of left- and right-circular polarizations (spin states) into states with opposite OAM. We present a method for converting arbitrary SAM states into total angular momentum states characterized by a superposition of independent OAM. We designed a metasurface that converts left- and right-circular polarizations into states with independent values of OAM and designed another device that performs this operation for elliptically polarized states. These results illustrate a general material-mediated connection between SAM and OAM of light and may find applications in producing complex structured light and in optical communication.

On-chip discrimination of orbital angular momentum of light with plasmonic nanoslits

Nanoscale ◽  
2016 ◽  
Vol 8 (4) ◽  
pp. 2227-2233 ◽  
Author(s):  
Shengtao Mei ◽  
Kun Huang ◽  
Hong Liu ◽  
Fei Qin ◽  
Muhammad Q. Mehmood ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Optical Communication ◽  
Communication System ◽  
Degree Of Freedom ◽  
System Capacity ◽  
Optical Communication System ◽  
On Chip

The orbital angular momentum (OAM) of light can be taken as an independent and orthogonal degree of freedom for multiplexing in an optical communication system, potentially improving the system capacity to hundreds of Tbits per second.

Orbital angular momentum-driven anomalous Hall effect

2021 ◽  
Author(s):  
Oliver Dowinton ◽  
Mohammad Bahramy
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Transition Metal Oxides ◽  
Magnetic State ◽  
Magnetic Moments ◽  
Anomalous Hall Effect ◽  
Ferromagnetic State ◽  
Periodic Systems ◽  
Spin States ◽  
Berry Curvature

Abstract Orbital angular momentum (OAM) plays a central role in regulating the magnetic state of electrons in non-periodic systems such as atoms and molecules. In solids, on the other hand, OAM is usually quenched by the crystal field, and thus, has a negligible effect on magnetisation. Accordingly, it is generally neglected in discussions around band topology such as Berry curvature (BC) and intrinsic anomalous Hall conductivity (AHC). Here, we present a theoretical framework demonstrating that crystalline OAM can be directionally unquenched in transition metal oxides via energetic proximity of the conducting d electrons to the local magnetic moments. We show that this leads to `composite' Fermi-pockets with topologically non-trivial OAM textures. This enables a giant Berry curvature with an intrinsic non-monotonic AHC, even in collinearly-ordered spin states. We use this model to explain the origin of the giant AHC observed in the forced-ferromagnetic state of EuTiO3 and propose it as a prototype for OAM driven AHC.

Rapid generation of perfect vortex beam without side lobes

2018 ◽  
Vol 32 (24) ◽  
pp. 1850289
Author(s):  
Siqi Li ◽  
Mulong Liu ◽  
Xingyi Li ◽  
Zhiqiang Ge ◽  
Lingxuan Zhang
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Optical Communication ◽  
Spatial Light Modulators ◽  
Vortex Beam ◽  
Digital Micromirror Device ◽  
Light Modulators ◽  
Rapid Generation ◽  
Rapid Switching ◽  
Topological Charges

We have proposed an approach for rapid generation of perfect vortex beam without side lobes through a digital micromirror device (DMD). Employing this method, the amplitude and phase of far field can be controlled indirectly by changing the rotation state of each unit on the DMD. The perfect vortex beams of equal rings diameter independent of their topological charges are generated commendably and the side lobes are avoided. Moreover, we have demonstrated rapid switching among the generated orbital angular momentum modes at the speed of 10 kHz, which is much faster than that of the usual method realized by spatial light modulators (SLMs). The proposed method is very beneficial for the optical communication and trapping or manipulating the small particle based on orbital angular momentum modes.

scholarly journals Ultrafast control of fractional orbital angular momentum of microlaser emissions

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Zhifeng Zhang ◽  
Haoqi Zhao ◽  
Danilo Gomes Pires ◽  
Xingdu Qiao ◽  
Zihe Gao ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Optical Communication ◽  
High Speed ◽  
Quantum Information Processing ◽  
Time Window ◽  
Gain Medium ◽  
Control Pulse ◽  
Processing Technologies ◽  
On Chip

Abstract On-chip integrated laser sources of structured light carrying fractional orbital angular momentum (FOAM) are highly desirable for the forefront development of optical communication and quantum information–processing technologies. While integrated vortex beam generators have been previously demonstrated in different optical settings, ultrafast control and sweep of FOAM light with low-power control, suitable for high-speed optical communication and computing, remains challenging. Here we demonstrate fast control of the FOAM from a vortex semiconductor microlaser based on fast transient mixing of integer laser vorticities induced by a control pulse. A continuous FOAM sweep between charge 0 and charge +2 is demonstrated in a 100 ps time window, with the ultimate speed limit being established by the carrier recombination time in the gain medium. Our results provide a new route to generating vortex microlasers carrying FOAM that are switchable at GHz frequencies by an ultrafast control pulse.

scholarly journals Proper relativistic position operators in 1+1 and 2+1 dimensions

2020 ◽  
Vol 35 (18) ◽  
pp. 2050084
Author(s):  
Taeseung Choi
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Wave Equations ◽  
Position Operator ◽  
Spin Angular Momentum ◽  
Particle Position ◽  
Constant Of Motion ◽  
Mass Moment ◽  
Relativistic Position ◽  
Canonical Position

We have revisited the Dirac theory in [Formula: see text] and [Formula: see text] dimensions by using the covariant representation of the parity-extended Poincaré group in their native dimensions. The parity operator plays a crucial role in deriving wave equations in both theories. We studied two position operators, a canonical one and a covariant one that becomes the particle position operator projected onto the particle subspace. In [Formula: see text] dimensions the particle position operator, not the canonical position operator, provides the conserved Lorentz generator. The mass moment defined by the canonical position operator needs an additional unphysical spin-like operator to become the conserved Lorentz generator in [Formula: see text] dimensions. In [Formula: see text] dimensions, the sum of the orbital angular momentum given by the canonical position operator and the spin angular momentum becomes a constant of motion. However, orbital and spin angular momentum do not conserve separately. On the other hand the orbital angular momentum given by the particle position operator and its corresponding spin angular momentum become a constant of motion separately.

scholarly journals Special Issue on Novel Insights into Orbital Angular Momentum Beams: From Fundamentals, Devices to Applications

2019 ◽  
Vol 9 (13) ◽  
pp. 2600 ◽  
Author(s):  
Yang Yue ◽  
Hao Huang ◽  
Yongxiong Ren ◽  
Zhongqi Pan ◽  
Alan E. Willner
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Elementary Particles ◽  
Spin Angular Momentum ◽  
Special Issue

It is well-known now that angular momentum carried by elementary particles can be categorized as spin angular momentum (SAM) and orbital angular momentum (OAM) [...]

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