Quantum Mechanical Properties of Light Fields Carrying Orbital Angular Momentum

Boyd, Robert W.; Padgett, Miles J.

doi:10.1007/978-3-319-31903-2_17

Cited by 3 publications

(3 citation statements)

References 45 publications

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“…Dynamical rotation of the electromagnetic field of light with respect to the axis of propagation is described by a vector quantity called angular momentum associated as spin angular momentum (SAM) and orbital angular momentum (OAM). While SAM is attributed to the light beam polarization as elliptical or circular, OAM is corresponding with the twisting of the beam wave front around the propagation axis (coincident with a topological phase singularity); such a beam is called an optical vortex (OV). − The intensity profiles of OVs were made from donut-shaped concentric rings with zero-intensity at the center − associated with the beam phase singularity. At a given wavelength λ, the phase front of an OV beam is composed of | l | intertwined helices along the propagation axis, where the integer azimuthal index l gives the amount of OAM carried by the wave per photon as l ℏ. , …”

Section: Introductionmentioning

confidence: 99%

Theoretical Prediction of Umbilics Creation in Nematic Liquid Crystals with Positive Dielectric Anisotropy

Habibpourmoghadam

2019

ACS Omega

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Optically assisted electrical generation of umbilic defects, arising in homeotropically aligned nematic liquid crystal cells and known as topological templates for the generation of optical vortices, are reported in nematic liquid crystals with positive dielectric anisotropy in detail. It is shown that nematic liquid crystals with positive dielectric anisotropy can serve as a stable and efficient medium for the optical vortex generation from both linearly and circularly polarized input Gaussian beams. Hybrid cells made from a thin layer of nematic liquid crystal confined between a photoresponsive slab of iron-doped lithium niobate and a glass plate coated with an active material, i.e., indium tin oxide, were studied. Exposure to a laser beam locally induces a photovoltaic field in the iron-doped lithium niobate substrate, which can penetrate into the liquid crystal film and induce realignment of molecules. The photovoltaic field drives charge carrier accumulation at the interface of indium tin oxide with the liquid crystal, which effectively modifies the shape and symmetry of the electric field. The photovoltaic field has a continuous radial distribution in the transverse xy-plane, weakening with increasing distance from the light irradiation center, where the electric field is normal to the cell plane. Umbilics are created as a result of the liquid crystal tendency to realign parallel to the electric field. Numerical studies of the transmitted intensity profiles in between linear polarizers reveal optical vortex pattern (of four and eight brushes) characteristics for the umbilical defects. The application of crossed circular polarizers results in annular-shaped intensity patterns as a result of spin-to-orbital angular momentum conversions, which give rise to the optical vortices.

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Section: Introductionmentioning

confidence: 99%

Theoretical Prediction of Umbilics Creation in Nematic Liquid Crystals with Positive Dielectric Anisotropy

Habibpourmoghadam

2019

ACS Omega

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“…As previously noted, the topological charge of an optical vortex can have either positive or negative values; it is only technical limitations that place any upper bound on its magnitude, and values of up to several hundred have in fact been experimentally achieved. This capacity represents the basis for developments in a surprisingly large range, exploiting quantum aspects of the high-level modal symmetry associated with beam phase and transverse structure, as well as the quantized orbital angular momentum [156]. Some of the fields showing special promise include quantum computing and cryptography, optical communications, micro-rheology, materials characterization, nanofabrication, and bioimaging: a very brief summary follows.…”

Section: Discussionmentioning

confidence: 99%

Symmetry and Quantum Features in Optical Vortices

Andrews

2021

Symmetry

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Optical vortices are beams of laser light with screw symmetry in their wavefront. With a corresponding azimuthal dependence in optical phase, they convey orbital angular momentum, and their methods of production and applications have become one of the most rapidly accelerating areas in optical physics and technology. It has been established that the quantum nature of electromagnetic radiation extends to properties conveyed by each individual photon in such beams. It is therefore of interest to identify and characterize the symmetry aspects of the quantized fields of vortex radiation that relate to the beam and become manifest in its interactions with matter. Chirality is a prominent example of one such aspect; many other facets also invite attention. Fundamental CPT symmetry is satisfied throughout the field of optics, and it plays significantly into manifestations of chirality where spatial parity is broken; duality symmetry between electric and magnetic fields is also involved in the detailed representation. From more specific considerations of spatial inversion, amongst which it emerges that the topological charge has the character of a pseudoscalar, other elements of spatial symmetry, beyond simple parity inversion, prove to repay additional scrutiny. A photon-based perspective on these features enables regard to be given to the salient quantum operators, paying heed to quantum uncertainty limits of observables. The analysis supports a persistence in features of significance for the material interactions of vortex beams, which may indicate further scope for suitably tailored experimental design.

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“…As manufacturing methods for optical devices reach sub-wavelength precision, new possibilities have come to light to form the derivative of an optical signal: vortex plates [12,13]. By carving a spiral (stair-case like) cavity on the order of the light wavelength, one can generate vectorial beams [14,15,16,17]. When they are inserted on the focal plane of a thin lens, they can greatly improve the quality of the image from phase contrast imaging [18,19].…”

Section: Introductionmentioning

confidence: 99%

True optical spacial derivatives for plasma density measurements

Gourdain¹,

Erez²,

Evans³

et al. 2022

Preprint

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This paper shows analytically and numerically that a vortex plate coupled to a neutral density filter can deliver a true optical derivative when placed at the focal plane of a 2f lens pair. This technique turns spatial variations in intensity into an intensity, which square root is the spatial derivative of the initial intensity variation. More surprisingly, it also turns any spatial variations in phase into an intensity, which square root is the spatial derivative of the initial phase variation. Since the optical derivative drops the DC component of the signal, it is possible to measure the full electron plasma turbulence spectrum optically, without using any interferometer.

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Quantum Mechanical Properties of Light Fields Carrying Orbital Angular Momentum

Cited by 3 publications

References 45 publications

Theoretical Prediction of Umbilics Creation in Nematic Liquid Crystals with Positive Dielectric Anisotropy

Theoretical Prediction of Umbilics Creation in Nematic Liquid Crystals with Positive Dielectric Anisotropy

Symmetry and Quantum Features in Optical Vortices

True optical spacial derivatives for plasma density measurements

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