Journal articles: 'Light helicity'

1

Kovalev, Alexey A., Victor V. Kotlyar, and Alexey M. Telegin. "Optical Helicity of Light in the Tight Focus." Photonics 10, no. 7 (June 23, 2023): 719. http://dx.doi.org/10.3390/photonics10070719.

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Using the Richards–Wolf formalism, we obtain explicit analytical expressions for the optical helicity density at the tight focus of four different light beams: a linearly polarized optical vortex, an optical vortex with right-handed circular polarization, superposition of a cylindrical vector beam and a linearly polarized beam, and a beam with hybrid circular-azimuthal polarization. We show that, in all four cases, the helicity density at the focus is nonzero and has different signs in different focal plane areas. If the helicity density changes sign, then the full helicity of the beam (averaged over the beam cross section at the focus) is zero and is conserved upon propagation. We reveal that the full helicity is zero when the full longitudinal component of the spin angular momentum is zero. If the helicity density does not change sign at the focus, such as in a circularly polarized optical vortex, then it is equal to the intensity in the focus, with the full helicity being equal to the beam power and conserving upon propagation. Although the helicity is related to the polarization state distribution across the beam at the focus, the expressions for the helicity density are found to be different from those for the longitudinal component of the spin angular momentum for the beams of interest.

2

Bengtsson, A. K. H. "Light-front higher-helicity interactions." Fortschritte der Physik 60, no. 9-10 (February 29, 2012): 1038–43. http://dx.doi.org/10.1002/prop.201200035.

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Poulikakos, Lisa V., Jennifer A. Dionne, and Aitzol García-Etxarri. "Optical Helicity and Optical Chirality in Free Space and in the Presence of Matter." Symmetry 11, no. 9 (September 3, 2019): 1113. http://dx.doi.org/10.3390/sym11091113.

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The inherently weak nature of chiral light–matter interactions can be enhanced by orders of magnitude utilizing artificially-engineered nanophotonic structures. These structures enable high spatial concentration of electromagnetic fields with controlled helicity and chirality. However, the effective design and optimization of nanostructures requires defining physical observables which quantify the degree of electromagnetic helicity and chirality. In this perspective, we discuss optical helicity, optical chirality, and their related conservation laws, describing situations in which each provides the most meaningful physical information in free space and in the context of chiral light–matter interactions. First, an instructive comparison is drawn to the concepts of momentum, force, and energy in classical mechanics. In free space, optical helicity closely parallels momentum, whereas optical chirality parallels force. In the presence of macroscopic matter, the optical helicity finds its optimal physical application in the case of lossless, dual-symmetric media, while, in contrast, the optical chirality provides physically observable information in the presence of lossy, dispersive media. Finally, based on numerical simulations of a gold and silicon nanosphere, we discuss how metallic and dielectric nanostructures can generate chiral electromagnetic fields upon interaction with chiral light, offering guidelines for the rational design of nanostructure-enhanced electromagnetic chirality.

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Crimin, Frances, Neel Mackinnon, Jörg Götte, and Stephen Barnett. "Optical Helicity and Chirality: Conservation and Sources." Applied Sciences 9, no. 5 (February 26, 2019): 828. http://dx.doi.org/10.3390/app9050828.

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We consider the helicity and chirality of the free electromagnetic field, and advocate the former as a means of characterising the interaction of chiral light with matter. This is in view of the intuitive quantum form of the helicity density operator, and of the dual symmetry transformation generated by its conservation. We go on to review the form of the helicity density and its associated continuity equation in free space, in the presence of local currents and charges, and upon interaction with bulk media, leading to characterisation of both microscopic and macroscopic sources of helicity.

5

Guadagnini, E. "Gravitational deflection of light and helicity asymmetry." Physics Letters B 548, no. 1-2 (November 2002): 19–23. http://dx.doi.org/10.1016/s0370-2693(02)02811-3.

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Hernández, Raúl Josué, Francisco J. Sevilla, Alfredo Mazzulla, Pasquale Pagliusi, Nicola Pellizzi, and Gabriella Cipparrone. "Collective motion of chiral Brownian particles controlled by a circularly-polarized laser beam." Soft Matter 16, no. 33 (2020): 7704–14. http://dx.doi.org/10.1039/c9sm02404b.

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Remote switching from passive to collective chiral-active motion by circularly-polarized light is shown for spherical polymeric Brownian particles. Light-propulsion is triggered by the coupling between the particle's chirality and the light helicity.

7

Krassnigg, A., and H. C. Pauli. "On helicity and spin on the light cone." Nuclear Physics B - Proceedings Supplements 108 (April 2002): 251–55. http://dx.doi.org/10.1016/s0920-5632(02)01338-5.

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Yu Yang, 于洋, 范之国 Fan Zhiguo, 徐少罕 u Shaohan, and 高隽 Gao Jun. "Study on Helicity Flip of Backscattered Circular Polarized Light." Chinese Journal of Lasers 42, no. 11 (2015): 1113004. http://dx.doi.org/10.3788/cjl201542.1113004.

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Dainone, Pambiang Abel, Nicholas Figueiredo Prestes, Pierre Renucci, Alexandre Bouché, Martina Morassi, Xavier Devaux, Markus Lindemann, et al. "Controlling the helicity of light by electrical magnetization switching." Nature 627, no. 8005 (March 27, 2024): 783–88. http://dx.doi.org/10.1038/s41586-024-07125-5.

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Kiemle, Jonas, Philipp Zimmermann, Alexander W. Holleitner, and Christoph Kastl. "Light-field and spin-orbit-driven currents in van der Waals materials." Nanophotonics 9, no. 9 (June 29, 2020): 2693–708. http://dx.doi.org/10.1515/nanoph-2020-0226.

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AbstractThis review aims to provide an overview over recent developments of light-driven currents with a focus on their application to layered van der Waals materials. In topological and spin-orbit dominated van der Waals materials helicity-driven and light-field-driven currents are relevant for nanophotonic applications from ultrafast detectors to on-chip current generators. The photon helicity allows addressing chiral and non-trivial surface states in topological systems, but also the valley degree of freedom in two-dimensional van der Waals materials. The underlying spin-orbit interactions break the spatiotemporal electrodynamic symmetries, such that directed currents can emerge after an ultrafast laser excitation. Equally, the light-field of few-cycle optical pulses can coherently drive the transport of charge carriers with sub-cycle precision by generating strong and directed electric fields on the atomic scale. Ultrafast light-driven currents may open up novel perspectives at the interface between photonics and ultrafast electronics.

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Sandoval-Santana, J. C., V. G. Ibarra-Sierra, H. Carrère, L. A. Bakaleinikov, V. K. Kalevich, E. L. Ivchenko, X. Marie, T. Amand, A. Balocchi, and A. Kunold. "Light helicity probed through spin dependent recombination in GaAsN alloys." Journal of Luminescence 251 (November 2022): 119163. http://dx.doi.org/10.1016/j.jlumin.2022.119163.

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Koksal, K., M. Babiker, V. E. Lembessis, and J. Yuan. "Hopf index and the helicity of elliptically polarized twisted light." Journal of the Optical Society of America B 39, no. 2 (January 10, 2022): 459. http://dx.doi.org/10.1364/josab.441732.

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Garoli, Denis, Pierfrancesco Zilio, Francesco De Angelis, and Yuri Gorodetski. "Helicity locking of chiral light emitted from a plasmonic nanotaper." Nanoscale 9, no. 21 (2017): 6965–69. http://dx.doi.org/10.1039/c7nr01674c.

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Wang, Jincheng, and Chunlei Guo. "Permanent recording of light helicity on optically inactive metal surfaces." Optics Letters 31, no. 24 (November 22, 2006): 3641. http://dx.doi.org/10.1364/ol.31.003641.

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15

Wu, Xing-Gang, and Tao Huang. "Pion Electromagnetic Form Factor in the KT Factorization Formulae." International Journal of Modern Physics A 21, no. 04 (February 10, 2006): 901–4. http://dx.doi.org/10.1142/s0217751x06032277.

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Based on the light-cone (LC) framework and the kT factorization formalism, the transverse momentum effects and the different helicity components' contributions to the pion form factor Fπ(Q2) are recalculated. In particular, the contribution to the pion form factor from the higher helicity components (λ1 + λ2 = ±1), which come from the spin-space Wigner rotation, are analyzed in the soft and hard energy regions respectively. Our results show that the right power behavior of the hard contribution from the higher helicity components can only be obtained by fully keeping the kT dependence in the hard amplitude, and that the kT dependence in LC wavefunction affects the hard and soft contributions substantially. A model for the twist-3 wavefunction ψp(x,k⊥) of the pion has been constructed based on the moment calculation by applying the QCD sum rules, whose distribution amplitude has a better end-point behavior than that of the asymptotic one. With this model wavefunction, the twist-3 contributions including both the usual helicity components (λ1 + λ2 = 0) and the higher helicity components (λ1 + λ2 = ±1) to the pion form factor have been studied within the modified pQCD approach. Our results show that the twist-3 contribution drops fast and it becomes less than the twist-2 contribution at Q2~10GeV2. The higher helicity components in the twist-3 wavefunction will give an extra suppression to the pion form factor. When all the power contributions, which include higher order in αs, higher helicities, higher twists in DA and etc., have been taken into account, it is expected that the hard contributions will fit the present experimental data well at the energy region where pQCD is applicable.

16

ZOLLER, V. R. "PROTON HELICITY FLOW TO MESONIC CLOUD AND AXIAL COUPLINGS OF BARYONS." Modern Physics Letters A 08, no. 12 (April 20, 1993): 1113–23. http://dx.doi.org/10.1142/s0217732393002592.

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We apply the relativistic light-cone perturbation theory to a flow of the helicity of baryons to the angular momentum of the mesonic cloud. Starting with the SU(6) symmetry, we find good description of the axial couplings in β-decay of hyperons. In the light-cone technique, the pattern of the spin-flip of nucleons differs significantly from that expected in the conventional non-relativistic models.

17

BOURRELY, CLAUDE, FRANCO BUCCELLA, and JACQUES SOFFER. "HOW IS TRANSVERSITY RELATED TO HELICITY FOR QUARKS AND ANTIQUARKS INSIDE THE PROTON?" Modern Physics Letters A 24, no. 24 (August 10, 2009): 1889–96. http://dx.doi.org/10.1142/s0217732309031302.

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We consider the quark and antiquark transversity distributions inside a polarized proton and study how they are expected to be related to the corresponding helicity distributions, both in sign and magnitude. Our considerations lead to simple predictions in good agreement with their first determination for light quarks from experimental data. We also give our predictions for the light antiquarks transversity distributions, so far unknown.

18

Pipin, V. V. "Advances in mean-field dynamo theories." Proceedings of the International Astronomical Union 8, S294 (August 2012): 375–86. http://dx.doi.org/10.1017/s1743921313002810.

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AbstractWe give a short introduction to the subject and review advances in understanding the basic ingredients of the mean-field dynamo theory. The discussion includes the recent analytic and numerical work in developments for the mean electromotive force of the turbulent flows and magnetic field, the nonlinear effects of the magnetic helicity, the non-local generation effects in the dynamo. We give an example of the mean-field solar dynamo model that incorporates the fairly complete expressions for the mean-electromotive force, the subsurface shear layer and the conservation of the total helicity. The model is used to shed light on the issues in the solar dynamo and on the future development of this field of research.

19

Aghapour, Sajad, Lars Andersson, and Kjell Rosquist. "Helicity, spin, and infra-zilch of light: A Lorentz covariant formulation." Annals of Physics 431 (August 2021): 168535. http://dx.doi.org/10.1016/j.aop.2021.168535.

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20

Nishizawa, N., K. Nishibayashi, and H. Munekata. "A spin light emitting diode incorporating ability of electrical helicity switching." Applied Physics Letters 104, no. 11 (March 17, 2014): 111102. http://dx.doi.org/10.1063/1.4868874.

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21

Goto, Taichi, and Mitsuteru Inoue. "Magnetophotonic crystal comprising electro-optical layer for controlling helicity of light." Journal of Applied Physics 111, no. 7 (April 2012): 07A913. http://dx.doi.org/10.1063/1.3672062.

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22

Cantoni, M., and C. Rinaldi. "Light helicity detection in MOS-based spin-photodiodes: An analytical model." Journal of Applied Physics 120, no. 10 (September 8, 2016): 104505. http://dx.doi.org/10.1063/1.4962204.

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23

BOJAK, I. "POLARIZED HADRO- AND PHOTOPRODUCTION OF HEAVY QUARKS IN NLO QCD." International Journal of Modern Physics A 18, no. 08 (March 30, 2003): 1477–80. http://dx.doi.org/10.1142/s0217751x03014940.

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We present the first calculation of the complete NLO QCD corrections to the production of heavy flavors with longitudinally polarized hadrons. This reaction can be used at RHIC to extract the gluon helicity density and may shed light on the "heavy quark enigma". The theoretical uncertainties are briefly discussed.

24

Jadczak, Joanna, Joanna Kutrowska-Girzycka, Janina J. Schindler, Joerg Debus, Kenji Watanabe, Takashi Taniguchi, Ching-Hwa Ho, and Leszek Bryja. "Investigations of Electron-Electron and Interlayer Electron-Phonon Coupling in van der Waals hBN/WSe2/hBN Heterostructures by Photoluminescence Excitation Experiments." Materials 14, no. 2 (January 15, 2021): 399. http://dx.doi.org/10.3390/ma14020399.

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Monolayers of transition metal dichalcogenides (TMDs) with their unique physical properties are very promising for future applications in novel electronic devices. In TMDs monolayers, strong and opposite spin splittings of the energy gaps at the K points allow for exciting carriers with various combinations of valley and spin indices using circularly polarized light, which can further be used in spintronics and valleytronics. The physical properties of van der Waals heterostructures composed of TMDs monolayers and hexagonal boron nitride (hBN) layers significantly depend on different kinds of interactions. Here, we report on observing both a strong increase in the emission intensity as well as a preservation of the helicity of the excitation light in the emission from hBN/WSe2/hBN heterostructures related to interlayer electron-phonon coupling. In combined low-temperature (T = 7 K) reflectivity contrast and photoluminescence excitation experiments, we find that the increase in the emission intensity is attributed to a double resonance, where the laser excitation and the combined Raman mode A′1 (WSe2) + ZO (hBN) are in resonance with the excited (2s) and ground (1s) states of the A exciton in a WSe2 monolayer. In reference to the 2s state, our interpretation is in contrast with previous reports, in which this state has been attributed to the hybrid exciton state existing only in the hBN-encapsulated WSe2 monolayer. Moreover, we observe that the electron-phonon coupling also enhances the helicity preservation of the exciting light in the emission of all observed excitonic complexes. The highest helicity preservation of more than 60% is obtained in the emission of the neutral biexciton and negatively charged exciton (trion) in its triplet state. Additionally, to the best of our knowledge, the strongly intensified emission of the neutral biexciton XX0 at double resonance condition is observed for the first time.

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ATWOOD, DAVID, GAD EILAM, and AMARJIT SONI. "PURE LEPTONIC RADIATIVE DECAYS B±, Ds→ℓνγ AND THE ANNIHILATION GRAPH." Modern Physics Letters A 11, no. 13 (April 30, 1996): 1061–67. http://dx.doi.org/10.1142/s0217732396001090.

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Pure leptonic radiative decays of heavy-light mesons are calculated using a very simple nonrelativistic model. For B± the dominant contribution originates from photon emission from light initial quark. Emission of the photon overcomes the helicity suppression and leads to Br (B±→ℓνγ)~3.5×10–6 (which is about 16 times more than Br (B±→µ+ν)). Also, we find Br (Ds→ℓνγ)~2.6×10–5. The importance of these reactions in clarifying the dynamics of the annihilation graph is emphasized.

26

Feng, Peng, and Jianqiao Xie. "Light-induced coherent magnon excitation in monolayer magnetic nanodots." International Journal of Modern Physics B 29, no. 08 (March 30, 2015): 1550055. http://dx.doi.org/10.1142/s0217979215500551.

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We develop a quantum theory to deal with the coherent magnon excitation in monolayer magnetic nanodots induced by a circularly polarized light. In our theoretical model, the exchange interaction, the magnetic dipole interaction and the light-matter interaction are all taken into account and an effective dynamic equations governing the magnon excitation is derived by a continuum approximation. Our theoretical model shows that the helicity of light and the magnetic dipole interaction govern the magnon excitation and result in the occurrence of various patterns for the spin z-component distribution. We present a scheme to manipulate the single-mode magnon excitation by properly tuning the light frequency.

27

Fehre, K., S. Eckart, M. Kunitski, M. Pitzer, S. Zeller, C. Janke, D. Trabert, et al. "Enantioselective fragmentation of an achiral molecule in a strong laser field." Science Advances 5, no. 3 (March 2019): eaau7923. http://dx.doi.org/10.1126/sciadv.aau7923.

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Chirality is omnipresent in living nature. On the single molecule level, the response of a chiral species to a chiral probe depends on their respective handedness. A prominent example is the difference in the interaction of a chiral molecule with left or right circularly polarized light. In the present study, we show by Coulomb explosion imaging that circularly polarized light can also induce a chiral fragmentation of a planar and thus achiral molecule. The observed enantiomer strongly depends on the orientation of the molecule with respect to the light propagation direction and the helicity of the ionizing light. This finding might trigger new approaches to improve laser-driven enantioselective chemical synthesis.

28

Nieto-Vesperinas, Manuel. "Non-zero helicity extinction in light scattered from achiral (or chiral) small particles located at points of null incident helicity density." Journal of Optics 19, no. 6 (May 2, 2017): 065402. http://dx.doi.org/10.1088/2040-8986/aa6528.

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Balitsky, I. I., and A. V. Radyushkin. "Light-ray evolution equations and leading-twist parton helicity-dependent nonforward distributions." Physics Letters B 413, no. 1-2 (November 1997): 114–21. http://dx.doi.org/10.1016/s0370-2693(97)01095-2.

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Zhang, Ruirui, Manna Gu, Rui Sun, Xiangyu Zeng, Yuqin Zhang, Yu Zhang, Chen Cheng, et al. "Plasmonic metasurfaces manipulating the two spin components from spin–orbit interactions of light with lattice field generations." Nanophotonics 11, no. 2 (December 13, 2021): 391–404. http://dx.doi.org/10.1515/nanoph-2021-0567.

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Abstract Artificial nanostructures in metasurfaces induce strong spin–orbit interactions (SOIs), by which incident circularly polarized light can be transformed into two opposite spin components. The component with an opposite helicity to the incident light acquires a geometric phase and is used to realize the versatile functions of the metasurfaces; however, the other component, with an identical helicity, is often neglected as a diffused background. Here, by simultaneously manipulating the two spin components originating from the SOI in plasmonic metasurfaces, independent wavefields in the primary and converted spin channels are achieved; the wavefield in the primary channel is controlled by tailoring the dynamic phase, and that in the converted channel is regulated by designing the Pancharatnam–Berry phase in concurrence with the dynamic phase. The scheme is realized by generating optical lattice fields with different topologies in two spin channels, with the metasurfaces composed of metal nanoslits within six round-apertures mimicking the multi-beam interference. This study demonstrates independent optical fields in a dual-spin channel based on the SOI effect in the metasurface, which provides a higher polarization degree of freedom to modify optical properties at the subwavelength scale.

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Masaki, Mitsuhiro, Hirokazu Maesaka, Kouichi Soutome, Shiro Takano, Takahiro Watanabe, Kouji Kubota, Takahiro Fujita, et al. "Adaptive feedforward control of closed orbit distortion caused by fast helicity-switching undulators." Journal of Synchrotron Radiation 28, no. 6 (October 21, 2021): 1758–68. http://dx.doi.org/10.1107/s160057752101047x.

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A new correction algorithm for closed orbit distortion based on an adaptive feedforward control (AFC) has been developed. At SPring-8, two helicity-switching twin-helical undulators (THUs) had been implemented with conventional feedforward corrections. However, the validity of these corrections turned out to be expiring due to unforeseen variation in the error magnetic fields with time. The developed AFC system has been applied to the THUs dynamically updating the feedforward table without stopping the helicity switching amid user experiments. The error sources in the two THUs are successfully resolved and corrected even while the two THUs are switching simultaneously with the same repetition period. The actual operation of the new AFC system enables us to keep the orbit variations suppressed with an accuracy at the sub-micrometre level in a transparent way for light source users.

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ABREU, E. M. C., A. CALIL, L. S. GRIGORIO, M. S. GUIMARAES, and C. WOTZASEK. "NEW ACTIONS FOR SELF-DUAL FIELDS IN 2D AND 3D." International Journal of Modern Physics A 23, no. 30 (December 10, 2008): 4829–40. http://dx.doi.org/10.1142/s0217751x08042870.

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New actions in D = 2 and D = 3 are proposed that are dual equivalent to known theories displaying well-defined chirality and helicity, respectively, along with new interpolating actions mapping continuously through the original dualities. The new chiral action in D = 2 is a second-order theory displaying the chiral constraint dynamically. In D = 3 the helicity constraint is imposed a la Siegel displaying a continuous mapping between the Maxwell–Chern–Simons and the self-dual model. It is also shown that the resulting theories introduce new versions of the Hull noton to take care of the symmetry aspects of the original models. The new interpolating formulation is then reexamined as a condensed phase for the discussion of duality under the light of the dual mechanisms — Julia–Toulouse and Higgs — establishing new interpolating actions in the dilute phase, according to these mechanisms.

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Georgoulis, Manolis K., Alexander Nindos, and Hongqi Zhang. "The source and engine of coronal mass ejections." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 377, no. 2148 (May 13, 2019): 20180094. http://dx.doi.org/10.1098/rsta.2018.0094.

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Coronal mass ejections (CMEs) are large-scale expulsions of coronal plasma and magnetic field propagating through the heliosphere. Because CMEs are observed by white-light coronagraphs which, by design, occult the solar disc, supporting disc observations (e.g. in EUV, soft X-rays, Halpha and radio) must be employed for the study of their source regions and early development phases. We review the key properties of CME sources and highlight a certain causal sequence of effects that may occur whenever a strong (flux-massive and sheared) magnetic polarity inversion line develops in the coronal base of eruptive active regions (ARs). Storing non-potential magnetic energy and helicity in a much more efficient way than ARs lacking strong polarity inversion lines, eruptive regions engage in an irreversible course, making eruptions inevitable and triggered when certain thresholds of free energy and helicity are crossed. This evolution favours the formation of pre-eruption magnetic flux ropes. We describe the steps of this plausible path to sketch a picture of the pre-eruptive phase of CMEs that may apply to most events, particularly the ones populating the high end of the energy/helicity distribution, that also tend to have the strongest space-weather implications. This article is part of the theme issue ‘Solar eruptions and their space weather impact’.

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Nieto-Vesperinas, Manuel. "Chiral optical fields: a unified formulation of helicity scattered from particles and dichroism enhancement." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 375, no. 2090 (March 28, 2017): 20160314. http://dx.doi.org/10.1098/rsta.2016.0314.

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We establish a general unified formulation which, using the optical theorem of electromagnetic helicity, shows that dichorism is a phenomenon arising in any scattering—or diffraction—process, elastic or not, of chiral electromagnetic fields by objects either chiral or achiral. It is shown how this approach paves the way to overcoming well-known limitations of standard circular dichroism, like its weak signal or the difficulties of using it with magnetodielectric particles. Based on the angular spectrum, representation of optical fields with only right circular or left circular plane waves, we introduce beams with transverse elliptic polarization and possessing a longitudinal component. Then, our formulation for general optical fields shows how to enhance the extinction rate of incident helicity (and therefore the dichroism signal) versus that of energy of the light scattered or emitted by a particle, or vice versa. This article is part of the themed issue ‘New horizons for nanophotonics’.

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Zhao, Yan, Bo Xu, Lianming Tong, and Jin Zhang. "The helicity of Raman scattered light: principles and applications in two-dimensional materials." Science China Chemistry 65, no. 2 (November 23, 2021): 269–83. http://dx.doi.org/10.1007/s11426-021-1119-4.

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Qian, X., B. Cao, Z. Wang, X. Shen, C. Soci, M. Eginligil, and T. Yu. "Carrier density and light helicity dependence of photocurrent in mono- and bilayer graphene." Semiconductor Science and Technology 33, no. 11 (October 15, 2018): 114008. http://dx.doi.org/10.1088/1361-6641/aae2f1.

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Abujetas, Diego R., and José A. Sánchez-Gil. "Spin Angular Momentum of Guided Light Induced by Transverse Confinement and Intrinsic Helicity." ACS Photonics 7, no. 2 (January 24, 2020): 534–45. http://dx.doi.org/10.1021/acsphotonics.0c00064.

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Fu, Hai-Bing, Wei Cheng, Rui-Yu Zhou, and Long Zeng. "D → P(π, K) helicity form factors within light-cone sum rule approach." Chinese Physics C 44, no. 11 (October 26, 2020): 113103. http://dx.doi.org/10.1088/1674-1137/abae4f.

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Besbas, Jean, Karan Banerjee, Jaesung Son, Yi Wang, Yang Wu, Matthew Brahlek, Nikesh Koirala, Jisoo Moon, Seongshik Oh, and Hyunsoo Yang. "Helicity‐Dependent Photovoltaic Effect in Bi 2 Se 3 Under Normal Incident Light." Advanced Optical Materials 4, no. 10 (July 8, 2016): 1642–50. http://dx.doi.org/10.1002/adom.201600301.

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Chan, K. T., N. G. Stephen, and S. R. Reid. "Helical structure of the waves propagating in a spinning Timoshenko beam." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 461, no. 2064 (October 4, 2005): 3913–34. http://dx.doi.org/10.1098/rspa.2005.1524.

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The aim of the paper is to study the cause of a frequency-splitting phenomenon that occurs in a spinning Timoshenko beam. The associated changes in the structure of the progressive waves are investigated to shed light on the relationship between the wave motion in a spinning beam and the whirling of a shaft. The main result is that travelling bending waves in a beam spinning about its central axis have the topological structure of a revolving helix traced by the centroidal axis with right-handed or left-handed chirality. Each beam element behaves like a gyroscopic disc in precession being rotated at the wave frequency with anticlockwise or clockwise helicity. The gyroscopic effect is identified as the cause of the frequency splitting and is shown to induce a coupling between two interacting travelling waves lying in mutually orthogonal planes. Two revolving waves travelling in the same direction in space appear, one at a higher and one at a lower frequency compared with the pre-split frequency value. With reference to a given spinning speed, taken as clockwise, the higher one revolves clockwise and the lower one has anticlockwise helicity, each wave being represented by a characteristic four-component vector wavefunction. Two factors are identified as important, the shear-deformation factor q and the gyroscopic-coupling phase factor θ . The q -factor is related to the wavenumber and the geometric shape of the helical wave. The θ -factor is related to the wave helicity and has two values, + π /2 and − π /2 corresponding to the anticlockwise and clockwise helicity, respectively. The frequency-splitting phenomenon is addressed by analogy with other physical phenomena such as the Jeffcott whirling shaft and the property of the local energy equality of a travelling wave. The relationship between Euler's formula and the present result relating to the helical properties of the waves is also explored.

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KANG, XIAN-WEI, HAI-BO LI, GONG-RU LU, and ALAKABHA DATTA. "STUDY OF CP VIOLATION IN $\Lambda_c^+$ DECAY." International Journal of Modern Physics A 26, no. 15 (June 20, 2011): 2523–35. http://dx.doi.org/10.1142/s0217751x11053432.

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In this paper, we study CP violation in [Formula: see text] and [Formula: see text] decays, where B, P and V denote a light spin-½ baryon, pseudoscalar and a vector meson respectively. In these processes the T odd CP violating triple-product (TP) correlations are examined. The genuine CP violating observables which are composed of the helicity amplitudes occurring in the angular distribution are constructed. Experimentally, by performing a full angular analysis it is shown how one may extract the helicity amplitudes and then obtain the TP asymmetries. We estimate the TP asymmetries in [Formula: see text] decays to be negligible in the Standard Model making these processes an excellent place to look for new physics. Taking a two-Higgs doublet model, as an example of new physics, we show that large TP asymmetries are possible in these decays. Finally, we discuss how BES-III and super τ-charm experiments will be sensitive to these CP violating signals in [Formula: see text] decays.

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Rees, Dylan, Kaustuv Manna, Baozhu Lu, Takahiro Morimoto, Horst Borrmann, Claudia Felser, J. E. Moore, Darius H. Torchinsky, and J. Orenstein. "Helicity-dependent photocurrents in the chiral Weyl semimetal RhSi." Science Advances 6, no. 29 (July 2020): eaba0509. http://dx.doi.org/10.1126/sciadv.aba0509.

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Weyl semimetals are crystals in which electron bands cross at isolated points in momentum space. Associated with each crossing point (or Weyl node) is a topological invariant known as the Berry monopole charge. The circular photogalvanic effect (CPGE), whereby circular polarized light generates a helicity-dependent photocurrent, is a notable example of a macroscopic property that emerges directly from the topology of the Weyl semimetal band structure. Recently, it was predicted that the amplitude of the CPGE associated with optical transitions near a Weyl node is proportional to its monopole charge. In chiral Weyl systems, nodes of opposite charge are nondegenerate, opening a window of wavelengths where the CPGE resulting from uncompensated Berry charge can emerge. Here, we report measurements of CPGE in the chiral Weyl semimetal RhSi, revealing a CPGE response in an energy window that closes at 0.65 eV, in agreement with the predictions of density functional theory.

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Nishizawa, Nozomi, Masaki Aoyama, Ronel C. Roca, Kazuhiro Nishibayashi, and Hiro Munekata. "Arbitrary helicity control of circularly polarized light from lateral-type spin-polarized light-emitting diodes at room temperature." Applied Physics Express 11, no. 5 (April 10, 2018): 053003. http://dx.doi.org/10.7567/apex.11.053003.

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Hanifeh, Mina, Mohammad Albooyeh, and Filippo Capolino. "Optimally Chiral Light: Upper Bound of Helicity Density of Structured Light for Chirality Detection of Matter at Nanoscale." ACS Photonics 7, no. 10 (September 10, 2020): 2682–91. http://dx.doi.org/10.1021/acsphotonics.0c00304.

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Ballesta-Garcia, Maria, Sara Peña-Gutiérrez, Pablo García-Gómez, and Santiago Royo. "Experimental Characterization of Polarized Light Backscattering in Fog Environments." Sensors 23, no. 21 (November 1, 2023): 8896. http://dx.doi.org/10.3390/s23218896.

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This paper focuses on the experimental characterization of the polarization behavior of light backscattered through fog. A polarimetric orthogonal state contrast imager and an active, purely polarized white illuminator system are used to evaluate both linear and circular polarization signals. The experiments are carried out in a macro-scale fog chamber under controlled artificial fog conditions. We explore the effect of backscattering in each imaging channel, and the persistence of both polarization signals as a function of meteorological visibility. We confirm the presence of the polarization memory effect with circularly polarized light, and, as a consequence, the maintenance of helicity in backscattering. Moreover, the circular cross-polarized channel is found to be the imaging channel less affected by fog backscattering. These results are useful and should be taken into account when considering active polarimetric imaging techniques for outdoor applications under foggy conditions.

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Taradin, Alexey, and Denis G. Baranov. "Chiral light in single-handed Fabry-Perot resonators." Journal of Physics: Conference Series 2015, no. 1 (November 1, 2021): 012012. http://dx.doi.org/10.1088/1742-6596/2015/1/012012.

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Abstract Chirality is a universal phenomenon that is encountered on many different length scales in nature. Interaction of chiral matter with chiral light results in the effect of circular dichroism, which underlies many techniques of discriminating molecular enantiomers. Enhancing dichroic effects is typically achieved by interfacing chiral matter with various optical resonators. In this context it is important to understand how the eigenmodes of optical cavities relate to the field states with well-defined handedness. Here, we present the model of a single-handedness chiral optical cavity supporting only an eigenmode of a given handedness without the presence of modes of other helicity. Resonant excitation of the cavity with light of appropriate handedness enables formation of a helical standing wave with a uniform chirality density, while the opposite handedness does not cause any resonant effects. Our findings expand the set of tools for investigations of chiral matter and open the door towards studies of chiral electromagnetic vacuum states.

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Forbes, Kayn A. "Optical helicity of unpolarized light." Physical Review A 105, no. 2 (February 25, 2022). http://dx.doi.org/10.1103/physreva.105.023524.

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Toyoda, Kohei, Fuyuto Takahashi, Shun Takizawa, Yu Tokizane, Katsuhiko Miyamoto, Ryuji Morita, and Takashige Omatsu. "Transfer of Light Helicity to Nanostructures." Physical Review Letters 110, no. 14 (April 5, 2013). http://dx.doi.org/10.1103/physrevlett.110.143603.

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Gorodnichev, E. E., and D. B. Rogozkin. "Weak Localization of Light in a Magneto-active Medium." JETP Letters, June 26, 2023. http://dx.doi.org/10.1134/s0021364023601665.

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The interference contribution to the optical conductance (total transmittance) of a sample of a disordered Faraday medium is calculated. The suppression of wave interference in a magnetic field is shown to be due to helicity-flip scattering events. The magnetic field does not destroy the interference of waves with a given helicity, but suppresses it if the helicity changes along different parts of the wave trajectory. This leads to a decrease in the interference contribution to the conductance with increasing the magnetic field. A similar phenomenon, negative magnetoresistance, is known as a consequence of weak localization of electrons in metals with impurities. It is found that, as the magnetic field increases, the change in the interference correction to the optical conductance tends to a certain limiting value, which depends on the ratio of the transport mean free path to the helicity-flip scattering mean free path. We also discuss the possibility of controlling the transition to the regime of strong “Anderson” localization in the quasi-one-dimensional case by means of the field.

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Chen, Jiamin, Xing Cheng, Zhixuan Cheng, Ziruo Wang, Minglai Li, Xionghui Jia, Yuqia Ran, Yanping Li, and Lun Dai. "Optical Helicity and Polarization Dependent NIR Negative Photocurrent in the 2D Magnetic Semiconductor CrI₃." Advanced Optical Materials, October 16, 2023. http://dx.doi.org/10.1002/adom.202301488.

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AbstractTwo‐dimensional magnetic semiconductors provide a fascinating platform for studying magneto‐optoelectronic properties at the atomically thin limit and have potential in developing novel devices. In this paper, the superior negative photoconductivity (NPC) characteristics of graphene‐CrI3‐graphene van der Waals heterostructure in light detection, such as a broader detection range (650–1250 nm) and faster response time (<0.32 ms), as well as light helicity and polarization sensitivity are reported. Under near‐infrared (NIR) light illumination, the NPC‐related photoresponsivity R and specific detectivity D* are 1.18 A W−1 and 1.26 × 109 Jones, respectively. Under magnetic field conditions, the NPC and positive photoconductivity (PPC) show opposite optical helicity dependence. The photoresponsivity helicity of the NPC‐dominated photocurrent can reach 16.01%. Besides, NPC and PPC show obvious and similar linear polarization dependence, independent of magnetic fields. It is demonstrated that NPC is superior to PPC in some aspects, such as fast detection of red and NIR lights as well as their helicity and polarization, especially in the NIR region. This work explores many unique phenomena of NPC, further revealing the interplay between magnetic and optoelectronic properties in CrI3, and paves the way for expanding traditional photoelectric detection and optical communication with higher data transmission rates.

Journal articles on the topic 'Light helicity'

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