The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Ido Kaminer - One of the best experts on this subject based on the ideXlab platform.
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shaping quantum photonic states using Free Electrons
Science Advances, 2021Co-Authors: Ben A Hayun, Ori Reinhardt, Jonathan Nemirovsky, Aviv Karnieli, Nicholas Rivera, Ido KaminerAbstract:It is a long-standing goal to create light with unique quantum properties such as squeezing and entanglement. We propose the generation of quantum light using Free-electron interactions, going beyond their already ubiquitous use in generating classical light. This concept is motivated by developments in electron microscopy, which recently demonstrated quantum Free-electron interactions with light in photonic cavities. Such electron microscopes provide platforms for shaping quantum states of light through a judicious choice of the input light and electron states. Specifically, we show how electron energy combs implement photon displacement operations, creating displaced-Fock and displaced-squeezed states. We develop the theory for consecutive electron-cavity interactions with a common cavity and show how to generate any target Fock state. Looking forward, exploiting the degrees of Freedom of Electrons, light, and their interaction may achieve complete control over the quantum state of the generated light, leading to novel light statistics and correlations.
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toward quantum optics with Free Electrons
Optics & Photonics News, 2020Co-Authors: Kangpeng Wang, Ido Kaminer, Raphael Dahan, Shai Tsesses, Ori Reinhardt, Saar Nehemia, Ofer Kfir, Hugo Lourencomartins, Armin Feist, Claus RopersAbstract:The weak coupling between Free Electrons and light remains the limiting factor that has prevented access to versatile electron–photon physics, such as the entanglement of individual photons and Electrons. This year, we demonstrated that photonic cavities can increase the coupling strength of Electrons and light by more than an order of magnitude.
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Coherent interaction between Free Electrons and a photonic cavity.
Nature, 2020Co-Authors: Kangpeng Wang, Raphael Dahan, Michael Shentcis, Yaron Kauffmann, Shai Tsesses, Adi Ben Hayun, Ori Reinhardt, Ido KaminerAbstract:Since its inception, research of cavity quantum electrodynamics (CQED) has extended our understanding of light-matter interactions and our ability to utilize them. Thus far, all the work in this field has been focused on light interacting with bound electron systems - such as atoms, molecules, quantum dots, and quantum circuits. In contrast, markedly different physical phenomena are found in Free-electron systems, the energy distribution of which is continuous and not discrete, implying tunable transitions and selection rules. In addition to their uses for electron microscopy, the interaction of Free Electrons with light enables important phenomena such as Cherenkov radiation, Compton scattering, and Free-electron lasing. However, no experiment has shown the integration of Free Electrons into the framework of CQED, because the fundamental electron-light interaction is limited in strength and lifetime. This limit explains why many phenomena have remained out of reach for experiments with Free Electrons. In this work, we developed the platform for studying CQED at the nanoscale with Free Electrons and demonstrated it by observing their coherent interaction with cavity photons for the first time. We also directly measure the cavity photon lifetime via a Free electron probe and show more than an order of magnitude enhancement in the electron-photon interaction strength. These capabilities may open new paths toward using Free Electrons as carriers of quantum information, even more so after strong coupling between Free Electrons and cavity photons will have been demonstrated. Efficient electron-cavity photon coupling could also allow new nonlinear phenomena of cavity opto-electro-mechanics and the ultrafast exploration of soft matter or other beam-sensitive materials using low electron current and low laser exposure.
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coherent interaction between Free Electrons and a photonic cavity
Nature, 2020Co-Authors: Kangpeng Wang, Raphael Dahan, Michael Shentcis, Yaron Kauffmann, Shai Tsesses, Adi Ben Hayun, Ori Reinhardt, Ido KaminerAbstract:Advances in the research of interactions between ultrafast Free Electrons and light have introduced a previously unknown kind of quantum matter, quantum Free-electron wavepackets1-5. So far, studies of the interactions of cavity-confined light with quantum matter have focused on bound electron systems, such as atoms, quantum dots and quantum circuits, which are considerably limited by their fixed energy states, spectral range and selection rules. By contrast, quantum Free-electron wavepackets have no such limits, but so far no experiment has shown the influence of a photonic cavity on quantum Free-electron wavepackets. Here we develop a platform for multidimensional nanoscale imaging and spectroscopy of Free-electron interactions with photonic cavities. We directly measure the cavity-photon lifetime via a coherent Free-electron probe and observe an enhancement of more than an order of magnitude in the interaction strength relative to previous experiments of electron-photon interactions. Our Free-electron probe resolves the spatiotemporal and energy-momentum information of the interaction. The quantum nature of the Electrons is verified by spatially mapping Rabi oscillations of the electron spectrum. The interactions between Free Electrons and cavity photons could enable low-dose, ultrafast electron microscopy of soft matter or other beam-sensitive materials. Such interactions may also open paths towards using Free Electrons for quantum information processing and quantum sensing. Future studies could achieve Free-electron strong coupling6,7, photon quantum state synthesis8 and quantum nonlinear phenomena such as cavity electro-optomechanics9.
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Free Electrons radiation in a photonic time crystal
Conference on Lasers and Electro-Optics, 2020Co-Authors: Alex Dikopoltsev, Ido Kaminer, Shai Tsesses, Yonatan Sharabi, Mordechai SegevAbstract:We present novel radiation emission by Free Electrons moving in a spatiotemporally modulated medium, which in specific cases acts as a photonic time crystal. We observe two regimes of radiation, subluminal and superluminal.
James M Cordes - One of the best experts on this subject based on the ideXlab platform.
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ne2001 ii using radio propagation data to construct a model for the galactic distribution of Free Electrons
arXiv: Astrophysics, 2003Co-Authors: James M Cordes, T J W LazioAbstract:In Paper I we present a new model for the Galactic distribution of Free Electrons. In this paper we describe the input data and methodology for determining the structure and parameters of the model. Tables of the input data are provided and several figures are used to demonstrate why particular Galactic structures are needed. We identify lines of sight on which discrete regions either enhance or diminish the dispersion or the scattering. Most do not coincide with known \ion{H}{2} regions or supershells, most likely because the enhancements correspond to column densities smaller than detection thresholds for the emission measure in recombination-line surveys.
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ne2001 i a new model for the galactic distribution of Free Electrons and its fluctuations
arXiv: Astrophysics, 2002Co-Authors: James M Cordes, T J W LazioAbstract:We present a new model for the Galactic distribution of Free Electrons. It (a) describes the distribution of the Free Electrons responsible for pulsar dispersion measures and thus can be used for estimating the distances to pulsars; (b) describes large-scale variations in the strength of fluctuations in electron density that underly interstellar scattering; (c) can be used to interpret interstellar scattering and scintillation observations of Galactic objects and of extragalactic objects, such as intrinsically compact AGNs and Gamma-ray burst afterglows; and (d) serves as a preliminary, smooth spatial model of the warm ionized component of the interstellar gas. This work builds upon and supercedes the Taylor & Cordes (1993) model by exploiting new observations and analysis methods. For lines of sight directed out of the Galactic plane, the new model yields substantially larger values for pulsar dispersion measures, except for directions dominated by the local hot bubble. Unlike the TC93 model, the new model provides sufficient Electrons to account for the dispersion measures of the vast majority of known, Galactic pulsars. The new model is described and exemplified using plots of astronomically useful quantities on Galactic-coordinate grids. Software available on the Internet is also described. Future observations and analysis techniques that will improve the Galactic model are outlined.
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hyperstrong radio wave scattering in the galactic center ii a likelihood analysis of Free Electrons in the galactic center
The Astrophysical Journal, 1998Co-Authors: Joseph T W Lazio, James M CordesAbstract:The scattering diameters of Sgr A* and several nearby OH masers (≈ 1'' at 1 GHz) indicate that a region of enhanced scattering is along the line of sight to the Galactic center. We combine radio-wave scattering data and Free-Free emission and absorption measurements in a likelihood analysis that constrains the following parameters of the GC scattering region: The GC-scattering region separation, ΔGC; the angular extent of the region, ψl and ψb; the outer scale on which density fluctuations occur, l0; and the gas temperature, Te. The maximum likelihood estimates of these parameters are ΔGC=133−80+200 pc, 05≤ψl1°, and (l0/1 pc)2/3Te−1/2=10-7±0.8 . The parameter ψb was not well constrained, and we adopt ψb = 05. The close correspondence between ΔGC and ψl DGC suggests that the scattering region encloses the GC. As host media for the scattering, we consider the photoionized surface layers of molecular clouds and the interfaces between molecular clouds and the 107 K ambient gas. We are unable to make an unambiguous determination, but we favor the interface model in which the scattering medium is hot (Te ~ 106 K) and dense (ne ~ 10 cm-3). The GC scattering region produces a 1 GHz scattering diameter for an extragalactic source of 90'', if the region is a single screen, or 180'', if the region wraps around the GC, as appears probable. We modify the Taylor-Cordes model for the Galactic distribution of Free Electrons in order to include an explicit GC component. We predict that pulsars seen through this region will have a dispersion measure of approximately 2000 pc cm-3, of which approximately 1500 pc cm-3 arises from the GC component itself. We stress the uniqueness of the GC scattering region, probably resulting from the high-pressure environment in the GC.
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hyperstrong radio wave scattering in the galactic center ii a likelihood analysis of Free Electrons in the galactic center
arXiv: Astrophysics, 1998Co-Authors: Joseph T W Lazio, James M CordesAbstract:The scattering diameters of Sgr A* and several nearby OH masers (~ 1" at 1 GHz) indicate that a region of enhanced scattering is along the line of sight to the Galactic center. We combine radio-wave scattering data and Free-Free emission and absorption measurements in a likelihood analysis that constrains the following parameters of the GC scattering region: The GC-scattering region separation, d; the angular extent of the region, \psi_l; the outer scale on which density fluctuations occur, l_0; and the gas temperature, T. The maximum likelihood estimates of these parameters are d = 133_{-80}^{+200} pc, 0.5 degrees <= \psi_l <~ 1 degrees, and (l_0/1 pc)^{2/3}T^{-1/2} = 10^{-7 +/- 0.8}. As host media for the scattering, we consider the photoionized surface layers of molecular clouds and the interfaces between molecular clouds and the 10^7 K ambient gas. We are unable to make an unambiguous determination, but we favor an interface model in which the scattering medium is hot (T ~ 10^6 K) and dense (n_e ~ 10 cm^{-3}). The GC scattering region produces a 1 GHz scattering diameter for an extragalactic source of 90", if the region is a single screen, or 180", if the region wraps around the GC, as appears probable. We modify the Taylor-Cordes model for the Galactic distribution of Free Electrons in order to include an explicit GC component. Pulsars seen through this region will have a dispersion measure of approximately 2000 pc cm^{-3}, of which 75% arises from the GC component. We stress the uniqueness of the GC scattering region, probably resulting from the high-pressure environment in the GC.
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pulsar distances and the galactic distribution of Free Electrons
The Astrophysical Journal, 1993Co-Authors: J H Taylor, James M CordesAbstract:We describe a quantitative model for the distribution of Free Electrons in the Galaxy, with particular emphasis on its utility for estimating pulsar distances from dispersion measures. Contrary to past practice, we abandon the assumption of an axisymmetric Galaxy. Instead, we explicitly incorporate spiral arms, the shapes and locations of which are derived from existing radio and optical observations of H II regions. Additional parameters of the model include the electron densities of outer and inner axisymmetric components, as well as of the spiral arms; scale lengths for the r- and z-dependences of the axisymmetric features and the width and scale height of the arms; and fluctuation parameters used to relate the dispersion and scattering contributions of the outer, inner, and spiral arm components of the model
Claus Ropers - One of the best experts on this subject based on the ideXlab platform.
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optical coherence transfer mediated by Free Electrons
Science Advances, 2021Co-Authors: Ofer Kfir, Claus Ropers, Javier Garcia F De Abajo, Valerio Di GiulioAbstract:We theoretically investigate the quantum-coherence properties of the cathodoluminescence (CL) emission produced by a temporally modulated electron beam. Specifically, we consider the quantum-optical correlations of CL produced by Electrons that are previously shaped by a laser field. Our main prediction is the presence of phase correlations between the emitted CL field and the electron-modulating laser, even though the emission intensity and spectral profile are independent of the electron state. In addition, the coherence of the CL field extends to harmonics of the laser frequency. Since electron beams can be focused to below 1 A, their ability to transfer optical coherence could enable the ultra-precise excitation, manipulation, and spectrally resolved probing of nanoscale quantum systems.
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toward quantum optics with Free Electrons
Optics & Photonics News, 2020Co-Authors: Kangpeng Wang, Ido Kaminer, Raphael Dahan, Shai Tsesses, Ori Reinhardt, Saar Nehemia, Ofer Kfir, Hugo Lourencomartins, Armin Feist, Claus RopersAbstract:The weak coupling between Free Electrons and light remains the limiting factor that has prevented access to versatile electron–photon physics, such as the entanglement of individual photons and Electrons. This year, we demonstrated that photonic cavities can increase the coupling strength of Electrons and light by more than an order of magnitude.
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controlling Free Electrons with optical whispering gallery modes
Nature, 2020Co-Authors: Ofer Kfir, Hugo Lourencomartins, Armin Feist, Claus Ropers, Gero Storeck, Murat Sivis, Tyler R Harvey, Tobias J KippenbergAbstract:Free-electron beams are versatile probes of microscopic structure and composition1,2, and have revolutionized atomic-scale imaging in several fields, from solid-state physics to structural biology3. Over the past decade, the manipulation and interaction of Electrons with optical fields have enabled considerable progress in imaging methods4, near-field electron acceleration5,6, and four-dimensional microscopy techniques with high temporal and spatial resolution7. However, electron beams typically couple only weakly to optical excitations, and emerging applications in electron control and sensing8-11 require large enhancements using tailored fields and interactions. Here we couple a Free-electron beam to a travelling-wave resonant cavity mode. The enhanced interaction with the optical whispering-gallery modes of dielectric microresonators induces a strong phase modulation on co-propagating Electrons, which leads to a spectral broadening of 700 electronvolts, corresponding to the absorption and emission of hundreds of photons. By mapping the near-field interaction with ultrashort electron pulses in space and time, we trace the lifetime of the the microresonator following a femtosecond excitation and observe the spectral response of the cavity. The natural matching of Free Electrons to these quintessential optical modes could enable the application of integrated photonics technology in electron microscopy, with broad implications for attosecond structuring, probing quantum emitters and possible electron-light entanglement.
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controlling Free Electrons with optical whispering gallery modes
Conference on Lasers and Electro-Optics, 2020Co-Authors: Ofer Kfir, Hugo Lourencomartins, Armin Feist, Gero Storeck, Murat Sivis, Tyler R Harvey, Tobias J Kippenberg, Claus RopersAbstract:We show that optical microcavities drive strong coherent modulations the in co-propagating Free-electron beams, with sidebands spanning over 700eV from a sub-μm-long interaction. The Electrons probe the cavity's ringdown time and distinguish the modes spectrally.
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controlling Free Electrons with optical whispering gallery modes
arXiv: Optics, 2019Co-Authors: Ofer Kfir, Hugo Lourencomartins, Armin Feist, Gero Storeck, Murat Sivis, Tyler R Harvey, Tobias J Kippenberg, Claus RopersAbstract:Free-electron beams serve as uniquely versatile probes of microscopic structure and composition, and have repeatedly revolutionized atomic-scale imaging, from solid-state physics to structural biology. Over the past decade, the manipulation and interaction of Electrons with optical fields has seen significant progress, enabling novel imaging methods, schemes of near-field electron acceleration, and culminating in 4D microscopy techniques with both high temporal and spatial resolution. However, weak coupling strengths of electron beams to optical excitations are a standing issue for existing and emerging applications of optical Free-electron control. Here, we demonstrate phase matched near-field coupling of a Free-electron beam to optical whispering gallery modes of dielectric microresonators. The cavity-enhanced interaction with these optically excited modes imprints a strong phase modulation on co-propagating Electrons, which leads to electron-energy sidebands up to hundreds of photon orders and a spectral broadening of 700 eV. Mapping the near-field interaction with ultrashort electron pulses in space and time, we trace the temporal ring-down of the microresonator following a femtosecond excitation and observe the cavity's resonant spectral response. Resonantly enhancing the coupling of Electrons and light via optical cavities, with efficient injection and extraction, can open up novel applications such as continuous-wave acceleration, attosecond structuring, and real-time all-optical electron detection.
P. Kurian - One of the best experts on this subject based on the ideXlab platform.
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Quantum field theory treatment of magnetic effects on a system of Free Electrons
Journal of Magnetism and Magnetic Materials, 2018Co-Authors: C. Verzegnassi, Renan Germano, P. KurianAbstract:Abstract The effects of a magnetic field on the energy and on the spin of Free Electrons are computed in the theoretical framework of quantum field theory. In the case of a static moderate field and with relatively slow Electrons, the derived formulae are particularly simple. A comparison with the approaches of classical physics and of quantum mechanics shows essential differences and important analogies. The relevance to the magnetic effects of the initial polarization components of the electron states and the possible existence of special values of these quantities are discussed in the final conclusions, which might be useful to explain recent experiments on quasi-Free Electrons in chiral systems in biology.
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Chirality-energy conversion induced by magnetic effects on Free Electrons in quantum field theory
arXiv: General Physics, 2017Co-Authors: P. Kurian, C. VerzegnassiAbstract:Magnetic effects on Free electron systems have been studied extensively in the context of spin-to-orbital angular momentum conversion. Using a quantum field theory framework, we derive a similar relationship in the non-relativistic limit for the energy of Electrons with momentum directed along the axis of a spatiotemporally constant, weak magnetic field. For a single electron the expectation value of the maximum energy shift, which is fixed by our defined chirality index of the electron state, is computed perturbatively to first order as about 15% of the electron rest mass. This effect is orders of magnitude larger than that predicted by the quantum mechanical Zeeman shift. We then show, in the low-mass approximation, an analogous conversion between energy and chirality for a system of Free Electrons and suggest possible experimental tests of this phenomenon in electron states encountered across multiple physics disciplines.
Steve Arscott - One of the best experts on this subject based on the ideXlab platform.
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spin and recombination dynamics of excitons and Free Electrons in p type gaas effect of carrier density
Applied Physics Letters, 2017Co-Authors: F Cadiz, D Lagarde, P Renucci, D Paget, T Amand, Helene Carrere, A C H Rowe, Steve ArscottAbstract:Carrier and spin recombination are investigated in p-type GaAs of acceptor concentration NA = 1.5 × 1017 cm−3 using time-resolved photoluminescence spectroscopy at 15 K. At low photocarrier concentration, acceptors are mostly neutral and photoElectrons can either recombine with holes bound to acceptors (e-A0 line) or form excitons which are mostly trapped on neutral acceptors forming the (A0X) complex. It is found that the spin relaxation is faster for Free Electrons that recombine through the e-A0 transition due to exchange scattering with either trapped or Free holes, whereas spin flip processes are less likely to occur once the electron forms with a Free hole an exciton bound to a neutral acceptor. An increase in the photocarrier concentration induces a cross-over to a regime where the bimolecular band-to-band (b-b) emission becomes more favorable due to screening of the electron-hole Coulomb interaction and ionization of excitonic complexes and Free excitons. Then, the formation of excitons is no long...
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Spin and recombination dynamics of excitons and Free Electrons in p-type GaAs: Effect of carrier density
Applied Physics Letters, 2017Co-Authors: F Cadiz, D Lagarde, P Renucci, D Paget, T Amand, Helene Carrere, H. Rowe, Steve ArscottAbstract:Carrier and spin recombination are investigated in p-type GaAs of acceptor concentration NA = 1.5 × 1017 cm−3 using time-resolved photoluminescence spectroscopy at 15 K. At low photocarrier concentration, acceptors are mostly neutral and photoElectrons can either recombine with holes bound to acceptors (e-A0 line) or form excitons which are mostly trapped on neutral acceptors forming the (A0X) complex. It is found that the spin relaxation is faster for Free Electrons that recombine through the e-A0 transition due to exchange scattering with either trapped or Free holes, whereas spin flip processes are less likely to occur once the electron forms with a Free hole an exciton bound to a neutral acceptor. An increase in the photocarrier concentration induces a cross-over to a regime where the bimolecular band-to-band (b-b) emission becomes more favorable due to screening of the electron-hole Coulomb interaction and ionization of excitonic complexes and Free excitons. Then, the formation of excitons is no longer possible, the carrier recombination lifetime increases and the spin lifetime is found to decrease dramatically with a concentration due to fast spin relaxation with Free photoholes. In this high density regime, both the Electrons that recombine through the e-A0 transition and through the b-b transition have the same spin relaxation time.
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spin and recombination dynamics of excitons and Free Electrons in p type gaas effect of carrier density
arXiv: Materials Science, 2016Co-Authors: F Cadiz, D Lagarde, P Renucci, D Paget, T Amand, Helene Carrere, A C H Rowe, Steve ArscottAbstract:Carrier and spin recombination are investigated in p-type GaAs of acceptor concentration NA = 1.5 x 10^(17) cm^(-3) using time-resolved photoluminescence spectroscopy at 15 K. At low pho- tocarrier concentration, acceptors are mostly neutral and photoElectrons can either recombine with holes bound to acceptors (e-A0 line) or form excitons which are mostly trapped on neutral acceptors forming the (A0X) complex. It is found that the spin lifetime is shorter for Electrons that recombine through the e-A0 transition due to spin relaxation generated by the exchange scattering of Free Electrons with either trapped or Free holes, whereas spin flip processes are less likely to occur once the electron forms with a Free hole an exciton bound to a neutral acceptor. An increase of exci- tation power induces a cross-over to a regime where the bimolecular band-to-band (b-b) emission becomes more favorable due to screening of the electron-hole Coulomb interaction and ionization of excitonic complexes and Free excitons. Then, the formation of excitons is no longer possible, the carrier recombination lifetime increases and the spin lifetime is found to decrease dramatically with concentration due to fast spin relaxation with Free photoholes. In this high density regime, both the Electrons that recombine through the e-A0 transition and through the b-b transition have the same spin relaxation time.
