Victor N. Zadkov

• Professor, Director Institute of Spectroscopy of the Russian Academy of Sciences
• Director at Institute of Spectroscopy of the Russian Academy of Sciences

Quasicrystals are unique systems that, unlike periodic structures, lack translational symmetry but exhibit long-range order dramatically enriching the system properties. While evolution of light in the bulk of photonic quasicrystals is well studied, experimental evidences of light localization near the edge of truncated photonic quasicrystal struct...

Quasicrystals are unique systems that, unlike periodic structures, lack translational symmetry but exhibit long-range order dramatically enriching the system properties. While evolution of light in the bulk of photonic quasicrystals is well studied, experimental evidences of light localization near the edge of truncated photonic quasicrystal struct...

The quantum Zeno effect refers to the slowdown of the decay of a quantum system due to frequent measurements. It has been extended beyond quantum systems, manifesting itself in such phenomena as the suppression of output beam decay by sufficiently strong absorption introduced in guiding optical systems. In this case, the phenomenon is termed as mac...

Introduction of controllable deformations into periodic materials that lead to disclinations in their structure opens novel routes for construction of higher-order topological insulators hosting topological states at disclinations. Appearance of these topological states is consistent with the bulk-disclination correspondence principle, and is due t...

The quantum Zeno effect refers to slowing down of the decay of a quantum system that is affected by frequent measurements. Nowadays, the significance of this paradigm is extended far beyond quantum systems, where it was introduced, finding physical and mathematical analogies in such phenomena as the suppression of output beam decay by sufficiently...

Floquet systems with periodically varying in time parameters enable realization of unconventional topological phases that do not exist in static systems with constant parameters and that are frequently accompanied by appearance of novel types of the topological states. Among such Floquet systems are the Su-Schrieffer-Heeger lattices with periodical...

Floquet systems with periodically varying in time parameters enable realization of unconventional topological phases that do not exist in static systems with constant parameters and that are frequently accompanied by appearance of novel types of the topological states. Among such Floquet systems are the Su-Schrieffer-Heeger lattices with periodical...

We study both, experimentally and theoretically, propagation of light in the fs-laser written rotating square waveguide arrays and present the first experimental evidence of light localization induced by the rotation of periodic structure in the direction of light propagation. Such linear light localization occurs either in the corners of truncated...

Introduction of controllable deformations into periodic materials that lead to disclinations in their structure opens novel routes for construction of higher-order topological insulators hosting topological states at disclinations. Appearance of these topological states is consistent with the bulk-disclination correspondence principle, and is due t...

Исследованы особенности нелинейного распространения высокоинтенсивных импульсов коротковолнового инфракрасного диапазона в протяженных одномерных массивах волноводов с различными пространственными периодами, сформированных в плавленом кварце методом лазерной записи. Экспериментально зарегистрирована более чем десятикратная самокомпрессия фемтосекун...

We observe linear and nonlinear light localization at the edges and in the corners of truncated moiré arrays created by the superposition of periodic mutually twisted at Pythagorean angles square sublattices. Experimentally exciting corner linear modes in the femtosecond-laser written moiré arrays we find drastic differences in their localization p...

We observe linear and nonlinear light localization at the edges and in the corners of truncated moir\'e lattices created by the superposition of periodic mutually-twisted at Pythagorean angles square sublattices. Experimentally exciting corner linear modes in the fs-laser written moir\'e lattices we find drastic differences in their localization pr...

We report the experimental observation of the periodic switching of topological edge states between two dimerized fs-laser written waveguide arrays. Switching occurs due to the overlap of the modal fields of the edge states from topological forbidden gap, when they are simultaneously present in two arrays brought into close proximity. We found that...

We report the experimental observation of the periodic switching of topological edge states between two dimerized fs-laser written waveguide arrays. Switching occurs due to the overlap of the modal fields of the edge states from topological forbidden gap, when they are simultaneously present in two arrays brought into close proximity. We found that...

We report the experimental observation of nonlinear light localization and edge soliton formation at the edges of fs-laser written trimer waveguide arrays, where transition from non-topological to topological phases is controlled by the spacing between neighboring trimers. We found that, in the former regime, edge solitons occur only above a consid...

We report the experimental observation of nonlinear light localization and edge soliton formation at the edges of fs-laser written trimer waveguide arrays, where transition from nontopological to topological phases is controlled by the spacing between neighboring trimers.We found that, in the former regime, edge solitons occur only above a consider...

Russian science icon, Pyotr Lebedev, is well known for first proving the existence of light pressure by measuring its action on both solids and gases. His experiments are discussed here as well as comparison with later, independent light-pressure measurements in solids by Nichols and Hull and European scientists. These light pressure experiments we...

This review is devoted to the study of effects of quantum optics in nanostructures. The mechanisms by which the rates of radiative and nonradiative decay are modified are considered in the model of a two-level quantum emitter (QE) near a plasmonic nanoparticle (NP). The distributions of the intensity and polarization of the near field around an NP...

Multicolor flexible materials are in growing interest owing to the prominent fluorescence tunability and flexible adaptability. However, narrow band response and finite color transition limit the diverse application of multicolor flexible materials. Herein, flexible lanthanide ions-doped dual GdF3 composite with broadband light source response is s...

The effect of spherical SiO2 nanoparticles (NPs) embedded in the electrode layer of PEDOT:PSS on the efficiency of organic solar cells (OSC) based on small molecules was studied in detail. We show that embedding SiO2 NPs of 50 nm in diameter increases the power conversion efficiency (PCE) by 15%, and this increase weakly depends on the NPs concentr...

This review is devoted to studies of quantum optics effects for quantum emitters (QEs) in the near field of nanoparticles (NPs). In the simple model of a two-level QE located near a plasmon NP, we analyze the mechanisms for modifying the radiative and nonradiative decay rates and discuss the distribution of the near-field intensity and polarization...

The near-field polarization structure of a high-refractive-index dielectric nanosphere in a nonmagnetic and nonabsorbing medium is studied numerically in free space and in the vicinity of a flat dielectric substrate. Polarization patterns of the near field are obtained for linear and circular polarizations of the incident light and visualized using...

This book brings together reviews by internationally renowed experts on quantum optics and photonics. It describes novel experiments at the limit of single photons, and presents advances in this emerging research area. It also includes reprints and historical descriptions of some of the first pioneering experiments at a single-photon level and nonl...

The dual-mode emission and multicolor outputs in the time domain from core-shell microcrystals are presented. The core-shell microcrystals, with NaYF4:Yb/Er as the core and NaYF4:Ce/Tb/Eu as the shell, were successfully fabricated by employing the hydrothermal method, which confines the activator ions into a separate region and minimizes the effect...

We have studied the effect of spherical SiO2 nanoparticles with sizes of 20, 50, and 80 nm embedded in a PEDOT : PSS buffer layer on the performance of organic solar cells (OSCs) based on star-shaped oligomers. The current–voltage characteristics and absorption spectra of samples have been measured and analyzed; the morphology of the buffer layer s...

We studied the radiation-directivity pattern and the near-field polarization of a spheroidal metallic nanoparticle located over a silicon substrate by interaction with a linearly and circularly polarized field. It is shown that the directivity pattern of the spheroidal particle near the silicon substrate becomes strongly asymmetric and forward scat...

It is demonstrated that the interaction of a two-level quantum emitter (atom, molecule, etc) with a plasmonic nanoparticle (prolate nanospheroid) in an external laser field features either an essential increase (up to a few orders of magnitude) or reduction (up to a few times) of the total decay rate of the emitter in specific areas around the nano...

Structure of the near-field intensity and polarization distributions, the latter is described with the generalized 3D Stokes parameters, of a spherical Si subwavelength nanoparticle in a non-magnetic and non-absorbing media near a dielectric substrate has been studied in detail with the help of the Mie theory and an extension of the Weyl's method f...

In this paper we review recent progress in using plasmonic nanoparticles for improving efficiency of the organic photovoltaic (PV) cells with embedded plasmonic nanoparticles. Specifically, we discuss how the plasmonic nanoparticles can be used for guiding and concentrating the light for enhanced absorption, paying attention to both fundamentals an...

The scattered sunlight absorption efficacy by a solar cell with imbedded layer of spherical plasmonic nanoparticles is simulated versus the parameters of the imbedded particles, the material they are made of, their density and location in the polymeric buffer layer inclusive. It was shown that the embedded plasmonic nanoparticles cause an increase...

Analytical analysis of the near-field polarization distribution of a plasmonic prolate nanospheroid in a Gaussian beam is given. Polarization of the near-field is described with the help of the 3D generalized Stokes parameters, allowing simple visualization. It is shown that for a linearly polarized Gaussian beam with the lower mode TEM00, which fa...

The photon-number statistics from resonance fluorescence of a two-level atom near a metal nanosphere driven by a laser field with finite bandwidth is studied theoretically. Our analysis shows that all interesting physics here takes place in a small area around the nanosphere where the near field and the atom-nanosphere coupling essentially affect t...

Near-field polarization distribution of a plasmonic prolate nanospheroid in an incident electromagnetic field versus its polarization and the spheroid’s aspect ratio is studied in detail. Polarization of the near-field is described with the help of the 3D generalized Stokes parameters, allowing simple visualization. It is shown that this distributi...

A simple finite-dimensional geodynamo model, obtained from the equations of the mean field electrodynamics and reproducing the phenomenon of geomagnetic reversals, is proposed. It has been indicated that the reversal scale obtained in the scope of this model is rather close to the observed scale in its properties. The reversal mechanism is related...

On the basis of calculations of multipole moments of meta-atoms forming a planar metamaterial, a new method is proposed for the quantitative determination of its optical and polarisation properties. The efficiency of the method is demonstrated by the example of a planar metamaterial consisting of H-shaped nanoparticles.

Dynamics of atoms trapped in an optical dipole trap formed by a train of femtosecond laser pulses is studied in detail on example of Rb atoms. In computer simulation, it is proved that such a trap effectively confines the atoms at the pumping laser beam power in between 1 mW and 3 kW (pulse duration 100 fs). It is also shown that the resonant dipol...

Modification of the resonance fluorescence spec-trum of a two-level atom driving by a lasermonochromatic field in the close proximity of aplasmonic nanostructure (metal sphere) is studiedin detail. It is shown that one can control thisspectrum varying four key parameters: distancebetween the atom and the nanosphere, atom’s lo-cation around the nano...

We suggest a simple dynamical system which mimics a nonlinear dynamo which is able to provide (in specific domains of its parametric space) the temporal evolution of solar magnetic activity cycles as well as evolution of geomagnetic field including its polarity reversals. A qualitative explanation for the physical nature of both phenomena is presen...

Modification of the resonance fluorescence spectrum of a two-level atom driven by a monochromatic field in the close proximity of a plasmonic nanostructure (metal sphere) is studied in detail. It is shown that one can control this spectrum by varying several key parameters: (i) the radius of the nanosphere, (ii) polarization of the incident radiati...

The resonances of coherent population trapping (CPT) excited by a frequency-modulated (FM) field at the Zeeman sublevels during the transition F g = 2 → F e = 1 of the 87Rb D 1-absorption line were studied theoretically. The influence of the nonlinear Zeeman effect on the structure of the observed resonances was considered. The spectra of CPT reson...

Theoretical study and computer modeling results of the spectra of coherent dark resonances resulted from excitation of Zeeman sublevels of the Fg=2-->Fe=1 transition of the D1 line in 87Rb atoms by a frequency-modulated laser field are presented and discussed in detail. The influence of the nonlinear Zeeman effect on the structure of the coherent d...

ABSTRACT The results of frequency-modulation (FM) spectroscopy of coherent dark resonances from the Zeeman sublevels of the transition F=2 F=1 of D1 line in absorption of 87Rb atoms are presented and discussed in detail. By contrast with the conventional spectroscopy of coherent dark resonances employing two laser beams, relative frequency of which...

The universal algorithm of choosing the train of short laser pulses, which could selectively excite the specific enantiomers in a racemic mixture of rotationally cold molecules, is proposed. Its application is illustrated on example of laser control of content of different chiral conformations in the mixture of hydrogen peroxide molecules. Methods...

The concept of entangled quantum measurement was demonstrated by the example of the fundamental value of the experiment on quantum nondemolition measurement of a photon in a resonator with the use of a probe atom [1]. The quantum-information analysis of this experiment was performed. A mechanism of information transmission in the nondemolition meas...

It was shown recently by us that an isotropic distribution of molecules in gaseous media can be drastically effected via their orientation-dependent selective excitation by a strong femtosecond multicomponent laser pulse. In the present paper, we analyze the specific effects accompanying the dynamical orientation of molecules driven this way. It is...

The results of frequency-modulation (FM) spectroscopy of coherent dark resonances from the Zeeman sublevels of the transition F=2↔ F=1 of D 1 line in absorption of 87Rb atoms are presented and discussed in detail. By contrast with the conventional spectroscopy of coherent dark resonances employing two laser beams, relative frequency of which can be...

The general concept of generalized quantum measurements with minimal distortion of initial information, which was introduced in our earlier publication [1] is applied to the problem of continuous quantum variables measurement. The qualitative features of such measurements are revealed and compared with a standard completely dequantizing measurement...

We analyzed the absolute asymmetric synthesis (AAS) of enantiomers from an isotropic racemic mixture of chiral molecules, which employs the laser electrodipole interaction, and revealed a set of basic symmetry-based conditions on the parameters of field-molecule interaction. Using these conditions, we developed a novel scenario of the AAS (through...

The current status of studies in the physics of entangled states of atomic systems — an interdisciplinary field involving quantum optics, quantum information, and the foundations of quantum mechanics — is reviewed. In the first part of the review, an introduction to the theory of entangled states is given, their properties and applications are desc...

The concept of generalised quantum measurement is introduced as a transformation establishing the correspondence between the initial state of an object and the final state of the object—instrument system with the help of a classical information index one-to-one related to a classically compatible set of the states of the object—instrument system. I...

The method of selective destruction of small chiral molecules of a specified configuration, which is based on coherent action of the intense multicomponent ps and fs laser pulses, is suggested. Computer simulation results show its efficiency for the laser distillation of a racemic mixture of randomly oriented molecules in a gas phase at room temper...

The interaction of a three-level atom in the Λ configuration with a frequency-modulated (FM) field is analyzed theoretically for the first time. The two-frequency model for solving the problem of frequency mod- ulation spectroscopy of coherent dark resonances is described and analyzed for a three-level Λ system. The effectiveness of the two-frequen...

It is shown that the combined effects of electrostatic and resonant laser fields on a molecular ensemble can be used to control the orientation of molecules by changing their internal state. In contrast to most other schemes for controlling molecular orientation, the proposed method does not require rotational cooling and can be highly efficient at...

Dynamics of a three-level quantum system in Λ-configuration driven by a resonant laser field with and without frequency modulation (FM) is studied for the first time in detail using two simulation techniques – the density matrix and quantum trajectories analysis. This analysis was applied to the FM-spectroscopy of coherent dark resonances in Cs ato...

Information aspects of copying quantum states via stimulated emission of an optical quantum amplifier are considered. It is shown that the measurable information very rapidly decreases after amplification of a single photon up to a level of several photons. Spontaneous emission, which leads to such behavior, is also discussed.

We discuss applications of laser coherent control for asymmetric synthesis of enantiomers from a racemic mixture of chiral molecules. General symmetry requirements on the exciting laser field configurations are derived. Detailed calculations are made for the example of the simplest chiral hydrogen peroxide molecule, including laser distillation sce...

Theoretical study and computer simulation results for the stochastic dynamics of atoms localized in an optical dipole trap are presented. This dynamics is governed by the optical trap potential, cooling due to the Doppler effect, and heating due to the emission and absorption of virtual photons, i.e., due to the resonant dipole-dipole interactions...

A concept of the generalized quantum measurement is introduced as the transformation, which establishes a correspondence between the initial states of the object system and final states of the object--measuring device (meter) system with the help of a classical informational index, unambiguously linked to the classically compatible set of states of...

A special class of soft quantum measurements as a physical model of the fuzzy measurements widely used in physics is introduced and its information properties are studied in detail.

Possibilities of improving characteristics of quantum key distribution (QKD) protocols via variation of character set in quantum alphabets are investigated. QKD protocols with discrete alphabets letters of which form regular polyhedrons on the Bloch sphere (tetrahedron octahedron cube icosahedron and dodecahedron which have 4, 6, 8, 12, and 20 vert...

Possibilities of improving critical error rate of quantum key distribution (QKD) protocols for different strategies of eavesdropping are investigated. QKD-protocols with discrete alphabets letters of which form regular polyhedrons on the Bloch sphere (tetrahedron octahedron cube icosahedron and dodecahedron which have 4, 6, 8, 12 and 20 vertexes re...

We clarify the microscopic structure of the entangling quantum measurement superoperators and examine their possible physical realization in a simple three-qubit model, which implements the entangling quantum measurement with an arbitrary degree of entanglement.

The problem of increasing the critical error rate of quantum-cryptography protocols by varying a set of letters in a quantum alphabet for space of a fixed dimensionality is studied. Quantum alphabets forming regular polyhedra on the Bloch sphere and the continual alphabet equally including all the quantum states are considered. It is shown that, in...

Using hydrogen peroxide as an example, the specific features of the laser control of the chiral state of an initially racemic mixture of molecules without their preliminary orientation have been studied. The determining role of molecular rotations and the molecular ensemble temperature have been revealed, and promising schemes for the laser asymmet...

A quantum-information analysis of how the size and dimensionality of the quantum alphabet affect the critical error rate of the quantum-key-distribution (QKD) protocols is given on an example of two QKD protocols—the six-state and -state (i.e., a protocol with continuous alphabet) ones. In the case of a two-dimensional Hilbert space, it is shown th...

A novel quantum key distribution protocol (QKD) based on all unselected states of a quantum system that set the alphabet with a continuous set of letters is proposed. Employing all states of the Hilbert space leads to a maximum quantum uncertainty of transmitted states, and, therefore, an eavesdropper receives the minimum amount of information. For...

The concept of an entangling measurement as the most general form of ideal quantum measurement is introduced. The mathematical definition of an entangling measurement is given in the form of a superoperator transformation, which projects the initial states of an object-apparatus system on the corresponding entangled states appearing after a measure...

ABSTRACT We present the scheme of compatible quantum,information analysis of the quantum,key distribution (QKD) protocols, which give answers to the following questions: is it possible to improve the quantum bit error rate (QBER) of the 6-state protocol by employing more states, up to infinity, and can we essentially improve the QBER if the multidi...

A novel quantum key distribution (QKD) protocol, based on all unselected states of a quantum system, which set the alphabet with continuous set of letters, is proposed. Employing all states of the Hilbert space leads to the maximal quantum uncertainty of transmitted states and therefore an eavesdropper receives the minimal amount of information. Fo...

A new mechanism for controlling chiral states in simple chiral molecules with internal rotation, which employs the coherent quantum entanglement of the rotational-torsional states of the molecules, is proposed. It requires no preliminary spatial alignment of the molecules in a solution. A novel scenario for the preferential laser synthesis of enant...

The most general approaches to determining the quantitative measure of quantum information are analyzed based on physical content. Dynamic information is proposed as an alternative to coherent information. In a sense, the former corresponds to the use of a set of all possible states in the Hilbert space of a quantum system as the information availa...

This Special Issue of Journal of Optics B: Quantum and Semiclassical Optics brings together contributions of various researchers working on theoretical and experimental aspects of quantum optics and quantum entanglement. The physics of quantum entangled states, an interdisciplinary field of research involving quantum optics, physics of quantum inf...

We study the mathematical structure of superoperators describing quantum measurements, including the entangling measurement—the generalization of the standard quantum measurement that results in entangle-ment between the measurable system and apparatus. It is shown that the coherent information can be effec-tively used for the analysis of such enta...

The main quantum information measures are discussed with respect to their relation to physics. It is argued that the basic term to choose betweenthe possible ways to measure quantum information is compatibility/incompatibility of the quantum states, resulting in coherent information and here suggested compatible information measures. A sketch of in...

A new quantum cryptography protocol, based on all unselected states of a qubit as a sort of alphabet with continuous set of letters, is proposed. Its effectiveness is calculated and shown to be essentially higher than those of the other known protocols.

A universal theory for calculating coherent population trapping resonances in multilevel atoms is suggested. The theory allows arbitrary schemes of multilevel atoms and their excitations to be calculated taking into account the influence of relaxation effects in atoms, applied magnetic field, and the Doppler effect. The experimental data obtained b...

Basic quantum information measures involved in the information analysis of quantum systems are considered. It is shown that the main quantum information measurement methods depend on whether the corresponding quantum events are compatible or incompatible. For purely quantum channels, the coherent and compatible information measures, which are quali...

A new mechanism for controlling chiral states in simple chiral molecules with internal rotation, which employs the coherent quantum entanglement of the rotational–torsional states of the molecules, is proposed. It requires no preliminary spatial alignment of the molecules in a solution. A novel scenario for the preferential laser synthesis of enant...

A theoretical model of the coherent population trapping (CPT) in multilevel samarium atom and its comparison with experimental spectroscopic data are presented. Theoretical model describes a degenerated (Lambda) -system in Sm atom formed of the transitions 4f66s2(7F0) $ARLR 4f6(7F)6s6p(3P0)9F01 $ARLR 4f66s2(7F1) and includes also a fourth level 4f6...

Theoretical study and computer simulation results for stochastic dynamics of two atoms trapped in an optical dipole trap under action of a probe resonant radiation are presented. The radiation force correlations resulting form our model lead, in addition to cold collisions, to a tendency for atoms escape in pairs form the trap.