Rivka Bekenstein

Technion - Israel Institute of Technology, H̱efa, Haifa District, Israel

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Publications (18)50.98 Total impact

  • Nature Physics 01/2015; DOI:10.1038/nphys3196 · 20.60 Impact Factor
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    ABSTRACT: Self-accelerating beams-shape-preserving bending beams-are attracting great interest, offering applications in many areas such as particle micromanipulation, microscopy, induction of plasma channels, surface plasmons, laser machining, nonlinear frequency conversion and electron beams. Most of these applications involve light-matter interactions, hence their propagation range is limited by absorption. We propose loss-proof accelerating beams that overcome linear and nonlinear losses. These beams, as analytic solutions of Maxwell's equations with losses, propagate in absorbing media while maintaining their peak intensity. While the power such beams carry decays during propagation, the peak intensity and the structure of their main lobe region are maintained over large distances. We use these beams for manipulation of particles in fluids, steering the particles to steeper angles than ever demonstrated. Such beams offer many additional applications, such as loss-proof self-bending plasmons. In transparent media these beams show exponential intensity growth, which facilitates other novel applications in micromanipulation and ignition of nonlinear processes.
    Nature Communications 10/2014; 5:5189. DOI:10.1038/ncomms6189 · 10.74 Impact Factor
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    ABSTRACT: We introduce loss-proof shape-invariant nonparaxial accelerating beams that overcome both diffraction and absorption, and demonstrate their use in acceleration of microparticles inside liquids along curved trajectories that are significantly steeper than ever achieved.
    CLEO: Science and Innovations; 06/2014
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    ABSTRACT: We present non-paraxial shape-preserving accelerating electromagnetic wavepackets propagating in micro-sized curved surfaces, revealing exotic trajectories and polarization rotation dynamics caused by the interplay of interference effects and the curvature of space.
    CLEO: QELS_Fundamental Science; 06/2014
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    ABSTRACT: We demonstrate optical analogues of gravitational effects such as gravitational lensing, tidal forces and gravitational redshift in the Newton-Schrödinger mainframe, by utilizing long-range interactions between solitons and accelerating beams in nonlocal nonlinear media.
    CLEO: QELS_Fundamental Science; 06/2014
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    ABSTRACT: A recent experiment confirmed the 35 years old prediction of Airy-shaped electron beams that accelerate in the absence of any potential. Yet their most intriguing property remained unclear: will such electrons emit radiation in free-space?
    CLEO: QELS_Fundamental Science; 06/2014
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    ABSTRACT: We develop holographic methods to generate arbitrarily-shaped light intensity distributions inside photonic crystals slabs, through shaping the electromagnetic field launched at the facets of the crystal. The technique can be generalized to any photonic structure.
    CLEO: Science and Innovations; 06/2014
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    ABSTRACT: We present shape-preserving spatially accelerating electromagnetic wave packets in curved space: wave packets propagating along nongeodesic trajectories while periodically recovering their structure. These wave packets are solutions to the paraxial and nonparaxial wave equations in curved space. We analyze the dynamics of such beams propagating on surfaces of revolution, and find solutions that propagate along a variety of nongeodesic trajectories, with their intensity profile becoming narrower (or broader) in a scaled self-similar fashion. Such wave packets reflect the interplay between the curvature of space and interference effects. Finally, we extend this concept to nonlinear accelerating beams in curved space supported by the Kerr nonlinearity. Our study concentrates on optical settings, but the underlying concepts directly relate to general relativity.
    Physical Review X 03/2014; 4(1):011038. DOI:10.1103/PhysRevX.4.011038 · 8.39 Impact Factor
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    ABSTRACT: By utilizing long-range interactions between solitons and accelerating beams in thermal nonlocal nonlinear media we demonstrate optical analogues of gravitational effects, such as tidal forces, gravitational lensing and gravitational redshift.
    Nonlinear Photonics; 01/2014
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    ABSTRACT: We present shape-preserving spatially accelerating electromagnetic wavepackets in curved space: wavepackets propagating along non-geodesic trajectories while recovering their structure periodically. These wavepackets are solutions to the paraxial and non-paraxial wave equation in curved space. We analyze the dynamics of such beams propagating on surfaces of revolution, and find solutions that carry finite power. These solutions propagate along a variety of non-geodesic trajectories, reflecting the interplay between the curvature of space and interference effects, with their intensity profile becoming narrower (or broader) in a scaled self-similar fashion Finally, we extend this concept to nonlinear accelerating beams in curved space supported by the Kerr nonlinearity. Our study concentrates on optical settings, but the underlying concepts directly relate to General Relativity.
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    ABSTRACT: We introduce a new class of 1 & 2-dimensional beams that overcome both diffraction & absorption, enabling accelerating plasmons that maintain their intensity profile. In free space these beams exhibit a counterintuitive exponential intensity growth.
    CLEO: QELS_Fundamental Science; 06/2013
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    ABSTRACT: We present the first study on linear and nonlinear accelerating beams in curved space. These shape-invariant wavepackets propagate along various trajectories arising from the interplay between the curvature of space and the interference effects.
    CLEO: QELS_Fundamental Science; 06/2013
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    ABSTRACT: In 1958, a revolutionary paper by Aharonov and Bohm predicted a phase difference between two parts of an electron wavefunction even when being confined to a regime with no EM field. The Aharonov-Bohm effect was groundbreaking: proving that the EM vector potential is a real physical quantity, affecting the outcome of experiments not only through the EM fields extracted from it. But is the EM potential a real necessity for an Aharonov-Bohm-type effect? Can it exist in a potential-free system such as free-space? Here, we find self-accelerating wavepackets that are solutions of the free Dirac equation, for massive/massless fermions/bosons. These accelerating Dirac particles mimic the dynamics of a free-charge moving under a ``virtual'' EM field, even though no field is acting and there is no charge: the entire dynamics is a direct result of the initial conditions. We show that such particles display an effective Aharonov-Bohm effect caused by exactly the same ``virtual'' potential that also ``causes'' the acceleration. Altogether, along the trajectory, there is no way to distinguish between a real force and the self-induced force - it is real by all measurable quantities. This proves that one can create all effects induced by EM fields by only controlling the initial conditions of a wave pattern, while the dynamics is in free-space. These phenomena can be observed in various settings: e.g., optical waves in honeycomb photonic lattices or in hyperbolic metamaterials, and matter waves in honeycomb interference structures.
  • 12th European/French Israeli Symposium on Nonlinear and quantum Optics (FRISNO), Ein Gedi, Israel, February 2013; 02/2013
  • Optics and Photonics News 12/2012; 23(12):26.
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    ABSTRACT: We present the nondiffracting spatially accelerating solutions of the Maxwell equations. Such beams accelerate in a circular trajectory, thus generalizing the concept of Airy beams to the full domain of the wave equation. For both TE and TM polarizations, the beams exhibit shape-preserving bending which can have subwavelength features, and the Poynting vector of the main lobe displays a turn of more than 90°. We show that these accelerating beams are self-healing, analyze their properties, and find the new class of accelerating breathers: self-bending beams of periodically oscillating shapes. Finally, we emphasize that in their scalar form, these beams are the exact solutions for nondispersive accelerating wave packets of the most common wave equation describing time-harmonic waves. As such, this work has profound implications to many linear wave systems in nature, ranging from acoustic and elastic waves to surface waves in fluids and membranes.
    Physical Review Letters 04/2012; 108(16):163901. DOI:10.1103/PhysRevLett.108.163901 · 7.73 Impact Factor
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    ABSTRACT: We present the spatially accelerating solutions of the Maxwell equations. Such non-paraxial beams accelerate in a circular trajectory, thus generalizing the concept of Airy beams. For both TE and TM polarizations, the beams exhibit shape-preserving bending with sub-wavelength features, and the Poynting vector of the main lobe displays a turn of more than 90 degrees. We show that these accelerating beams are self-healing, analyze their properties, and compare to the paraxial Airy beams. Finally, we present the new family of periodic accelerating beams which can be constructed from our solutions.
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    Rivka Bekenstein, Mordechai Segev
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    ABSTRACT: We find self-accelerating beams in highly nonlocal nonlinear optical media, and show that their propagation dynamics is strongly affected by boundary conditions. Specifically for the thermal optical nonlinearity, the boundary conditions have a strong impact on the beam trajectory: they can increase the acceleration during propagation, or even cause beam bending in a direction opposite to the initial trajectory. Under strong self-focusing, the accelerating beam decomposes into a localized self-trapped beam propagating on an oscillatory trajectory and a second beam which accelerates in a different direction. We augment this study by investigating the effects caused by a finite aperture and by a nonlinear range of a finite extent.
    Optics Express 11/2011; 19(24):23706-15. DOI:10.1364/OE.19.023706 · 3.53 Impact Factor