Nikita Nefedkin

CUNY Graduate Center | CUNY

This article delves into the intricacies of nonreciprocity in a system composed of two superconducting qubits operating in a transmon regime and coupled to a 1-D waveguide. Nonreciprocity, characterized by asymmetric signal transmission, is a phenomenon of increasing interest in quantum technologies, as it enables one-way signal propagation and iso...

The requirements of next-generation wireless communications have been growing exponentially in recent years, not only in terms of data rates but also of reliability, latency, and massiveness. These demands have been inspiring new paradigms for hardware and for underlying communication protocols. In this context, metasurfaces have been enabling a ra...

Tailored time variations, nonlinearities and active elements can endow metasurfaces with unique opportunities for next-generation wireless communication systems, enriching the growing platform of reconfigurable intelligent surfaces.

Nonreciprocity originating from classical interactions among nonlinear scatterers has been attracting increasing attention in the quantum community, offering a promising tool to control excitation transfer for quantum information processing and quantum computing. In this work, we explore the possibility of realizing largely nonreciprocal total cros...

Nonreciprocity originating from classical interactions among nonlinear scatterers has been attracting increasing attention in the quantum community, offering a promising tool to control excitation transfer for quantum information processing and quantum computing. In this work, we explore the possibility of realizing largely nonreciprocal total cros...

With the development of quantum technologies and their broad applications, the phenomenon of reciprocity breaking has been evolving from an effective tool in classical wave optics and electrodynamics to a promising instrument also for the field of quantum computing and quantum information processing. In this work, nonreciprocal wave phenomena that...

Engineered intersubband transitions in semiconductor heterostructures featuring multiple quantum wells (MQWs) have been shown to support record-high second-order nonlinear susceptibilities. By integrating these materials in metasurfaces with tailored optical resonances, it is possible to further enhance photonic interactions, yielding giant nonline...

Recent developments in non-Hermitian physics offer exciting opportunities for a broad range of basic research and engineering applications relevant to the antennas and propagation community. In this article, we offer a tutorial geared toward introducing the unusual electromagnetic phenomena emerging in non-Hermitian systems, with a particular empha...

Optical nanoantennas, i.e., elements transforming localized light or waveguide modes into freely propagating fields and vice versa, are vital components for modern nanophotonics. Optical antennas have been demonstrated to cause the Dicke superradiance effect, i.e., collective spontaneous emission of quantum sources. However, the impact of coherent...

The physics of systems that cannot be described by a Hermitian Hamiltonian, has been attracting a great deal of attention in recent years, motivated by their nontrivial responses and by a plethora of applications for sensing, lasing, energy transfer/harvesting, topology and quantum networks. Electromagnetics is an inherently non-Hermitian research...

Optical supercavity modes (superstates), i.e., hybrid modes emerging from the strong coupling of two modes of an open cavity, can support ultranarrow lines in their scattering spectra associated with quasi bound states in the continuum (quasi‐BIC). These modes are of great interest for sensing applications as they enable compact systems with unprec...

We theoretically study the role of strong coupling between organic J-aggregated chromophore and a plasmonic nanostructure in the process of photobleaching suppression. We take into account the influence of vibrational degrees of freedom of nuclei in the molecules of J-aggregates in the Born--Markov approximation. We then show that in the strong cou...

Optical nanoantennas, i.e., elements transforming localized light or waveguide modes into freely propagating fields and vice versa, are vital components for modern nanophotonics. Recently optical antennas have been demonstrated to cause the Dicke superradiance effect, i.e., collective spontaneous emission of quantum sources. However, the impact of...

Distributed feedback (DFB) lasers exploiting plasmonic structures as cavities are basic elements for various applications from sensorics to optoelectronics. Here, the time response of a plasmonic DFB laser in the small‐signal modulation regime is studied. It is shown that the temporal period of the plasmonic DFB laser response can be equal to an in...

We study the second-order coherence function of a plasmonic nanoantenna fed by near-field of a single-photon source incoherently pumped in the continuous wave regime. We consider the case of a strong Purcell effect, when the single-photon source radiates almost entirely in the mode of a nanoantenna. We show that when the energy of thermal fluctuati...

The time response to an external signal is the main characteristic of optoelectronic devices that determines their maximum modulation frequency. The use of plasmonic structures provides the opportunity to significantly reduce the response time. In this paper, we study the temporal dynamics of a plasmonic distributed feedback laser consisting of a t...

An anomalously high photosensitivity of \({\text{Cd}}{{{\text{S}}}_{{{\text{1--}}x}}}{\text{S}}{{{\text{e}}}_{x}}\) granular films observed in the experiment is explained. It is assumed that the charge transfer mechanism based on surface states existing at the granule boundaries can be responsible for an anomalously high photocurrent-to-dark curren...

Plasmonic distributed-feedback lasers based on a two-dimensional periodic array of metallic nanostructures are the main candidate for nanoscale sources of coherent electromagnetic field. Strong localization of the electromagnetic field and the large radiation surface are good opportunities for achieving an ultrashort response time to the external a...

In this paper, we consider the nonlinear response to the external electromagnetic field of a plasmonic nanolaser consisting of a metallic nanoparticle interacting with a pumped active medium. We investigate plasmonic nanolaser dynamics in the regime of loss compensation, when at certain values of the magnitude and frequency of the external electrom...

In this work we consider the dynamics of an ensemble of two-level atoms that interact with finite-width resonator mode. The superradiant burst occurs under a wide range of parameters in such a system. However, if the initial phase distribution of dipole moments of N two-level atoms is random, not all atoms take part in the superradiant process, but...

In 1954, Dicke predicted that a system of quantum emitters confined to a subwavelength volume would produce a superradiant burst. For such a burst to occur, the emitters must be in the special Dicke state with zero dipole moment. We show that a superradiant burst may also arise for non-Dicke initial states with a nonzero dipole moment. Both for Dic...

We suggest a mechanism by which a superradiant burst emerges from a subwavelength array of nonlinear classical emitters that are not initially synchronized. The emitters interact via the field of their common radiative response. We show that only if the distribution of initial phases is not uniform does a non-zero field of radiative response arise,...