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Ido Kaminer

Publications and source records attributed to Ido Kaminer.

At least 73 records · Page 4Linked to original sources
arXiv2023

Multi-photon electron emission with non-classical light

Photon number distributions from classical and non-classical light sources have been studied extensively, yet their impact on photoemission processes is largely unexplored. In this article, we present measurements of electron number-distributions from metal needle tips illuminated with ultrashort light pulses of different photon quantum statistics. By varying the photon statistics of the exciting light field between classical (Poissonian) and quantum (super-Poissonian), we demonstrate that the measured electron distributions are changed substantially. Using single-mode bright squeezed vacuum light, we measure extreme statistics events with up to 65 electrons from one light pulse at a mean of 0.27 electrons per pulse - the likelihood for such an event equals $10^{-128}$ with Poissonian statistics. Changing the number of modes of the exciting bright squeezed vacuum light, we can tailor the electron-number distribution on demand. Most importantly, our results demonstrate that the photon statistics is imprinted from the driving light to the emitted electrons, opening the door to new sensor devices and to strong-field quantum optics with quantum light.

quant-ph↗
arXiv2023

Breakdown of effective-medium theory by a photonic spin Hall effect

Effective-medium theory pertains to the theoretical modelling of homogenization, which aims to replace an inhomogeneous structure of subwavelength-scale constituents with a homogeneous effective medium. The effective-medium theory is fundamental to various realms, including electromagnetics and material science, since it can largely decrease the complexity in the exploration of light-matter interactions by providing simple acceptable approximation. Generally, the effective-medium theory is thought to be applicable to any all-dielectric system with deep-subwavelength constituents, under the condition that the effective medium does not have a critical angle, at which the total internal reflection occurs. Here we reveal a fundamental breakdown of the effective-medium theory that can be applied in very general conditions: showing it for deep-subwavelength all-dielectric multilayers even without critical angle. Our finding relies on an exotic photonic spin Hall effect, which is shown to be ultra-sensitive to the stacking order of deep-subwavelength dielectric layers, since the spin-orbit interaction of light is dependent on slight phase accumulations during the wave propagation. Our results indicate that the photonic spin Hall effect could provide a promising and powerful tool for measuring structural defects for all-dielectric systems even in the extreme nanometer scale.

physics.optics↗
arXiv2023

Automated Search for Conjectures on Mathematical Constants using Analysis of Integer Sequences

Formulas involving fundamental mathematical constants had a great impact on various fields of science and mathematics, for example aiding in proofs of irrationality of constants. However, the discovery of such formulas has historically remained scarce, often perceived as an act of mathematical genius by great mathematicians such as Ramanujan, Euler, and Gauss. Recent efforts to automate the discovery of formulas for mathematical constants, such as the Ramanujan Machine project, relied on exhaustive search. Despite several successful discoveries, exhaustive search remains limited by the space of options that can be covered and by the need for vast amounts of computational resources. Here we propose a fundamentally different method to search for conjectures on mathematical constants: through analysis of integer sequences. We introduce the Enumerated Signed-continued-fraction Massey Approve (ESMA) algorithm, which builds on the Berlekamp-Massey algorithm to identify patterns in integer sequences that represent mathematical constants. The ESMA algorithm found various known formulas for $e, e^2, tan(1)$, and ratios of values of Bessel functions. The algorithm further discovered a large number of new conjectures for these constants, some providing simpler representations and some providing faster numerical convergence than the corresponding simple continued fractions. Along with the algorithm, we present mathematical tools for manipulating continued fractions. These connections enable us to characterize what space of constants can be found by ESMA and quantify its algorithmic advantage in certain scenarios. Altogether, this work continues in the development of augmenting mathematical intuition by computer algorithms, to help reveal mathematical structures and accelerate mathematical research.

math.NT↗
arXiv2023

Nonperturbative electromagnetic nonlinearities, n-photon reflectors, and Fock-state lasers based on deep-strong coupling of light and matter

Light and matter can now interact in a regime where their coupling is stronger than their bare energies. This deep-strong coupling (DSC) regime of quantum electrodynamics promises to challenge many conventional assumptions about the physics of light and matter. Here, we show how light and matter interactions in this regime give rise to electromagnetic nonlinearities dramatically different from those of naturally existing materials. Excitations in the DSC regime act as photons with a linear energy spectrum up to a critical excitation number, after which, the system suddenly becomes strongly anharmonic, thus acting as an effective intensity-dependent nonlinearity of an extremely high order. We show that this behavior allows for N-photon blockade (with $N \gg 1$), enabling qualitatively new kinds of quantum light sources. For example, this nonlinearity forms the basis for a new type of gain medium, which when integrated into a laser or maser, produces large Fock states (rather than coherent states). Such Fock states could in principle have photon numbers orders of magnitude larger than any realized previously, and would be protected from dissipation by a new type of equilibrium between nonlinear gain and linear loss. We discuss paths to experimental realization of the effects described here.

quant-ph↗
arXiv2023

Free-Electron Ramsey-Type Interferometry for Enhanced Amplitude and Phase imaging of Nearfields

The complex range of interactions between electrons and electromagnetic fields gave rise to countless scientific and technological advances. A prime example is photon-induced nearfield electron microscopy (PINEM), enabling the detection of confined electric fields in illuminated nanostructures with unprecedented spatial resolution. However, PINEM is limited by its dependence on strong fields, making it unsuitable for sensitive samples, and its inability to resolve complex phasor information. Here, we leverage the nonlinear, over-constrained nature of PINEM to present an algorithmic microscopy approach, achieving far superior nearfield imaging capabilities. Our algorithm relies on free-electron Ramsey-type interferometry to produce orders-of-magnitude improvement in sensitivity and ambiguity-immune nearfield phase reconstruction, both of which are optimal when the electron exhibits a fully quantum behavior. Our results demonstrate the potential of combining algorithmic approaches with novel modalities in electron microscopy, and may lead to various applications from imaging sensitive biological samples to performing full-field tomography of confined light.

physics.optics↗
arXiv2023

Bulk-plasmon-mediated free-electron radiation beyond the conventional formation time

Free-electron radiation is a fundamental photon emission process that is induced by fast-moving electrons interacting with optical media. Historically, it has been understood that, just like any other photon emission process, free-electron radiation must be constrained within a finite time interval known as the "formation time", whose concept is applicable to both Cherenkov radiation and transition radiation, the two basic mechanisms describing radiation from a bulk medium and from an interface, respectively. Here we reveal an alternative mechanism of free-electron radiation far beyond the previously defined formation time. It occurs when a fast electron crosses the interface between vacuum and a plasmonic medium supporting bulk plasmons. While emitted continuously from the crossing point on the interface - thus consistent with the features of transition radiation - the extra radiation beyond the conventional formation time is supported by a long tail of bulk plasmons following the electron's trajectory deep into the plasmonic medium. Such a plasmonic tail mixes surface and bulk effects, and provides a sustained channel for electron-interface interaction. These results also settle the historical debate in Ferrell radiation, regarding whether it is a surface or bulk effect, from transition radiation or plasmonic oscillation.

physics.comp-ph↗
arXiv2023

Free-electron interactions with photonic GKP states: universal control and quantum error correction

We show that the coherent interaction between free electrons and photons can be used for universal control of continuous-variable photonic quantum states in the form of Gottesman-Kitaev-Preskill (GKP) qubits. Specifically, we find that electron energy combs enable non-destructive measurements of the photonic state and can induce arbitrary gates. Moreover, a single electron interacting with multiple photonic modes can create highly entangled states such as Greenberger-Horne-Zeilinger states and cluster states of GKPs.

quant-ph↗
arXiv2023

Universal and ultrafast quantum computation based on free-electron-polariton blockade

Cavity quantum electrodynamics (QED), wherein a quantum emitter is coupled to electromagnetic cavity modes, is a powerful platform for implementing quantum sensors, memories, and networks. However, due to the fundamental tradeoff between gate fidelity and execution time, as well as limited scalability, the use of cavity-QED for quantum computation was overtaken by other architectures. Here, we introduce a new element into cavity-QED - a free charged particle, acting as a flying qubit. Using free electrons as a specific example, we demonstrate that our approach enables ultrafast, deterministic and universal discrete-variable quantum computation in a cavity-QED-based architecture, with potentially improved scalability. Our proposal hinges on a novel excitation blockade mechanism in a resonant interaction between a free-electron and a cavity polariton. This nonlinear interaction is faster by several orders of magnitude with respect to current photon-based cavity-QED gates, enjoys wide tunability and can demonstrate fidelities close to unity. Furthermore, our scheme is ubiquitous to any cavity nonlinearity, either due to light-matter coupling as in the Jaynes-Cummings model or due to photon-photon interactions as in a Kerr-type many-body system. In addition to promising advancements in cavity-QED quantum computation, our approach paves the way towards ultrafast and deterministic generation of highly-entangled photonic graph states and is applicable to other quantum technologies involving cavity-QED.

quant-ph↗
arXiv2023

Free-electron Brewster radiation

Free-electron radiation offers an enticing route to create light emission at arbitrary spectral regime. However, this type of light emission is generally weak, which is intrinsically limited by the weak particle-matter interaction and unavoidably impedes the development of many promising applications, such as the miniaturization of free-electron radiation sources and high-energy particle detectors. Here we reveal a mechanism to enhance the particle-matter interaction by exploiting the pseudo-Brewster effect of gain materials - presenting an enhancement of at least four orders of magnitude for the light emission. This mechanism is enabled by the emergence of an unprecedented phase diagram that maps all phenomena of free-electron radiation into three distinct phases in a gain-thickness parameter space, namely the conventional, intermediate, and Brewster phases, when an electron penetrates a dielectric slab with a modest gain and a finite thickness. Essentially, our revealed mechanism corresponds to the free-electron radiation in the Brewster phase, which also uniquely features ultrahigh directionality, always at the Brewster angle, regardless of the electron velocity. Counterintuitively, we find that the intensity of this free-electron Brewster radiation is insensitive to the Fabry-Perot resonance condition and thus the variation of slab thickness, and moreover, a weaker gain could lead to a stronger enhancement for the light emission. The scheme of free-electron Brewster radiation, especially along with its compatibility with low-energy electrons, may enable the development of high-directionality high-intensity light sources at any frequency.

physics.optics↗
arXiv2023

Free-electron superfluorescence: collective optical dynamics at deep-subwavelength resolution

Long-range coherence and correlations between electrons in solids are the cornerstones for developing future quantum materials and devices. In 1954, Dicke described correlated spontaneous emission from closely packed quantum emitters, forming the theoretical basis of superradiance and superfluorescence. Since then, it has remained an open challenge to observe such phenomena with nanometer spatial resolution, precisely the important scale at which the collective correlations occur. Here, we report the first instance of free-electron-driven superfluorescence - superfluorescent cathodoluminescence - enabling us to excite and observe correlations at nanometer spatial scales. To exemplify this concept in our experiments, superlattices of lead halide perovskite quantum dots are excited by focused pulses of multiple free electrons. The electrons trigger superfluorescence: collective ultrafast emission observed at rates faster than both the lifetime and decoherence time. By controlling the area illuminated by the electron beam, we create a transition from a non-correlated spontaneous emission to a correlated superfluorescent emission. The observed signatures of superfluorescence are a reduction of the intrinsic emitter lifetime, a narrower linewidth, and a distinct redshift. We develop the theory of superfluorescent cathodoluminescence, which matches the results and highlights the unique features of electron-driven versus light-driven superfluorescence. Our observation and theory introduce a novel way to characterize coherence and correlations in quantum materials with nanometer spatial resolution, a key for future engineering of quantum devices.

physics.atm-clus↗
arXiv2022

Low-velocity-favored transition radiation

When a charged particle penetrates through an optical interface, photon emissions emerge - a phenomenon known as transition radiation. Being paramount to fundamental physics, transition radiation has enabled many applications from high-energy particle identification to novel light sources. A rule of thumb in transition radiation is that the radiation intensity generally decreases with the particle velocity v; as a result, low-energy particles are not favored in practice. Here we find that there exist situations where transition radiation from particles with extremely low velocities (e.g. v/c<0.001) exhibits comparable intensity as that from high-energy particles (e.g. v/c=0.999), where c is light speed in free space. The comparable radiation intensity implies an extremely high photon extraction efficiency from low-energy particles, up to eight orders of magnitude larger than that from high-energy particles. This exotic phenomenon of low-velocity-favored transition radiation originates from the excitation of Ferrell-Berreman modes in epsilon-near-zero materials. Our findings may provide a promising route towards the design of integrated light sources based on low-energy electrons and specialized detectors for beyond-standard-model particles.

physics.optics↗
arXiv2022

Photon-statistics force in ultrafast electron dynamics

In strong-field physics and attosecond science, intense light induces ultrafast electron dynamics. Such ultrafast dynamics of electrons in matter is at the core of phenomena such as high harmonic generation (HHG), where these dynamics lead to emission of extreme UV bursts with attosecond duration. So far, all ultrafast dynamics of matter were understood to originate purely from the classical vector potential of the driving light, disregarding the influence of the quantum nature of light. Here we show that dynamics of matter driven by bright (intense) light significantly depend on the quantum state of the driving light, which induces an effective photon-statistics force. To provide a unified framework for the analysis & control over such a force, we extend the strong-field approximation (SFA) theory to account for non-classical driving light. Our quantum SFA (qSFA) theory shows that in HHG, experimentally feasible squeezing of the driving light can shift & shape electronic trajectories and attosecond pulses at the scale of hundreds of attoseconds. Our work presents a new degree-of-freedom for attosecond spectroscopy, by relying on nonclassical electromagnetic fields, and more generally, introduces a direct connection between attosecond science and quantum optics.

physics.optics↗
arXiv2022

High harmonic generation driven by quantum light

High harmonic generation (HHG) is an extreme nonlinear process where intense pulses of light drive matter to emit high harmonics of the driving frequency, reaching the extreme ultraviolet (XUV) and x-ray spectral ranges. So far, the HHG process was always generated by intense laser pulses that are well described as a classical electromagnetic field. Advances in the generation of intense squeezed light motivate us to revisit the fundamentals of HHG and ask how the photon statistics of light may alter this process, and more generally alter the field of extreme nonlinear optics. The role of photon statistics in non-perturbative interactions of intense light with matter has remained unexplored in both experiments and theory. Here we show that the defining spectral characteristics of HHG, such as the plateau and cutoff, are sensitive to the photon statistics of the driving light. While coherent (classical) and Fock light states induce the established HHG cutoff law, thermal and squeezed states substantially surpass it, extending the cutoff compared to classical light of the same intensity. Hence, shaping the photon statistics of light enables producing far higher harmonics in HHG. We develop the theory of extreme nonlinear optics driven by squeezed light, and more generally by arbitrary quantum states of light. Our work introduces quantum optical concepts to strong-field physics as new degrees of freedom in the creation and control of HHG, and finally shows that experiments in this field are feasible. Looking forward, HHG driven by quantum light creates quantum states of XUV and X-rays, enabling applications of quantum optics in new spectral regimes.

physics.optics↗
arXiv2022

The Synthetic Hilbert Space of Laser-Driven Free-Electrons

Recent advances in laser interactions with coherent free electrons have enabled to shape the electron's quantum state. Each electron becomes a superposition of energy levels on an infinite quantized ladder, shown to contain up to thousands of energy levels. We propose to utilize the quantum nature of such laser-driven free electrons as a "synthetic Hilbert space" in which we construct and control qudits (quantum digits). The question that motivates our work is what qudit states can be accessed using electron-laser interactions, and whether it is possible to implement any arbitrary quantum gate. We find how to encode and manipulate free-electron qudit states, focusing on dimensions which are powers of 2, where the qudit represents multiple qubits implemented on the same single electron - algebraically separated, but physically joined. As an example, we prove the possibility to fully control a 4-dimenisonal qudit, and reveal the steps required for full control over any arbitrary dimension. Our work enriches the range of applications of free electrons in microscopy and spectroscopy, offering a new platform for continuous-variable quantum information.

quant-ph↗
arXiv2022

Light emission from strongly driven many-body systems

Strongly driven systems of emitters offer an attractive source of light over broad spectral ranges up to the X-ray region. A key limitation of these systems is that the light they emit is for the most part classical. We challenge this paradigm by building a quantum-optical theory of strongly driven many-body systems, showing that the presence of correlations among the emitters creates emission of nonclassical many-photon states of light. We consider the example of high-harmonic generation (HHG), by which a strongly driven system emits photons at integer multiples of the drive frequency. In the conventional case of uncorrelated emitters, the harmonics are in an almost perfectly multi-mode coherent state lacking any correlation between harmonics. By contrast, a correlation of the emitters prior to the strong drive is converted onto nonclassical features of the output light, including doubly-peaked photon statistics, ring-shaped Wigner functions, and quantum correlations between harmonics. We propose schemes for implementing these concepts, creating the correlations between emitters via an interaction between them or their joint interaction with the background electromagnetic field (as in superradiance). By tuning the time at which these processes are interrupted by the strong drive, one can control the amount of correlations between the emitters, and correspondingly the deviation of the emitted light from a classical state. Our work paves the way towards the engineering of novel many-photon states of light over a broadband spectrum of frequencies, and suggests HHG as a diagnostic tool for characterizing correlations in many-body systems with attosecond temporal resolution.

quant-ph↗
arXiv2022

Imaging the field inside nanophotonic devices

Controlling optical fields on the subwavelength scale is at the core of any nanophotonic device. Of particular interest are nanophotonic particle accelerators that promise a compact alternative to conventional radiofrequency-based accelerators. Efficient electron acceleration in such compact devices critically depends on achieving nanometer control of electron trajectories by precisely designed optical nearfields inside the device. However, these nearfields have so far been inaccessible due to the complexity of the devices and their geometrical constraints, hampering efforts to design and optimize future nanophotonic particle accelerators. Here we present the first measurement of the field distribution inside a nanophotonic accelerator. We develop a novel microscopy approach based on photon-induced nearfield electron microscopy (PINEM) to achieve frequency-tunable deep-subwavelength imaging of the nearfield inside nanophotonic accelerators. We compare the two leading designs of nanophotonic accelerators, also known as dielectric laser accelerators (DLAs): a dual-pillar structure with distributed Bragg reflector and an inverse-designed resonant structure. Our experiments are complemented by full 3D simulations, unveiling surprising deviations from the expected designs, showing complex field distributions related to intricate 3D features in the device and its fabrication tolerances. We further envision a tomography method to image the 3D field distribution, key for the future development of high-precision and hence high-efficiency DLA devices as well as other nanophotonic devices.

physics.acc-ph↗
arXiv2022

Compton Scattering Driven by Quantum Light

Compton scattering is one of the cornerstones of quantum physics, describing the fundamental interaction of a charged particle with photons. The Compton effect and its inverse are utilized in experiments driving free electrons by high intensity lasers to create trains of attosecond X-ray pulses. So far, all theory and experiments of the Compton effect and its generalizations have relied on electromagnetic fields that can be described classically. Advances in the generation of intense squeezed light could enable driving the Compton effect with non-classical light. This outlook motivates exploring the role of photon statistics in the Compton effect. We develop a framework to describe the full non-perturbative interaction of a charged particle with a driving field ascribed with an arbitrary quantum light state. We obtain analytical results for the Compton emission spectrum when driven by thermal and squeezed vacuum states, showing a noticeable broadening of the emission spectrum relative to a classical (coherent state) drive, thus reaching higher emission frequencies for the same average intensity. We envision utilizing the quantum properties of light, including photon statistics, squeezing, and entanglement, as novel degrees of freedom to control the wide range of radiation phenomena at the foundations of quantum electrodynamics.

quant-ph↗
arXiv2022

Superradiant Electron Energy Loss Spectroscopy

We analyze the interaction between a free electron and an ensemble of identical optical emitters. The mutual coherence and correlations between the emitters can enhance the interaction with each electron and become imprinted on its energy spectrum. We present schemes by which such collective interactions can be realized. As a possible application, we investigate free-electron interactions with superradiant systems, showing how electrons can probe the ultrafast population dynamics of superradiance.

quant-ph↗