arXiv subjects

Danil F. Kornovan

Publications and source records attributed to Danil F. Kornovan.

5 recordsLinked to original sources

arXiv2025

Towards a fictitious magnetic field trap for both ground and Rydberg state $^{87}$Rb atoms via the evanescent field of an optical nanofibre

Cold Rydberg atoms, known for their long lifetimes and strong dipole-dipole interactions that lead to the Rydberg blockade phenomenon, are among the most promising platforms for quantum simulations, quantum computation and quantum networks. However, a major limitation to the performance of Rydberg atom-based platforms is dephasing, which can be caused by atomic motion within the trap. Here, we propose a trap for $^{87}$Rb cold atoms that confines both the electronic ground state and a Rydberg state, engineered to minimize the differential light shifts between the two states. This is achieved by combining a fictitious magnetic field induced by optical nanofibre guided light and an external bias magnetic field. We calculate trap potentials for the cases of one- and two-guided modes with quasi-linear and quasi-circular polarisations, and calculate trap depths and trap frequencies for different values of laser power and bias fields. Moreover, we discuss the impact of the quadrupole polarisability of the Rydberg atoms on the trap potential and demonstrate how the size of a Rydberg atom influences the ponderomotive potential generated by the nanofibre-guided light field. This work expands on the idea of light-induced fictitious magnetic field traps and presents a practical approach for creating quantum networks using Rydberg atoms integrated with optical nanofibres to generate 1D atom arrays.

physics.atom-ph↗

arXiv2023

Excitation of $^{87}$Rb Rydberg atoms to nS and nD states (n$\leq$68) via an optical nanofiber

Cold Rydberg atoms are a promising platform for quantum technologies and combining them with optical waveguides has the potential to create robust quantum information devices. Here, we experimentally observe the excitation of cold rubidium atoms to a large range of Rydberg S and D states through interaction with the evanescent field of an optical nanofiber. We develop a theoretical model to account for experimental phenomena present such as the AC Stark shifts and the Casimir-Polder interaction. This work strengthens the knowledge of Rydberg atom interactions with optical nanofibers and is a critical step toward the implementation of all-fiber quantum networks and waveguide QED systems using highly excited atoms.

physics.atom-ph↗

arXiv2021

Multipole Born series approach to light scattering by Mie-resonant nanoparticle structures

Exciting optical effects such as polarization control, imaging, and holography were demonstrated at the nanoscale using the complex and irregular structures of nanoparticles with the multipole Mie-resonances in the optical range. The optical response of such particles can be simulated either by full wave numerical simulations or by the widely used analytical coupled multipole method (CMM), however, an analytical solution in the framework of CMM can be obtained only in a limited number of cases. In this paper, a modification of the CMM in the framework of the Born series and its applicability for simulation of light scattering by finite nanosphere structures, maintaining both dipole and quadrupole resonances, are investigated. The Born approximation simplifies an analytical consideration of various systems and helps shed light on physical processes ongoing in that systems. Using Mie theory and Green's functions approach, we analytically formulate the rigorous coupled dipole-quadrupole equations and their solution in the different-order Born approximations. We analyze in detail the resonant scattering by dielectric nanosphere structures such as dimer and ring to obtain the convergence conditions of the Born series and investigate how the physical characteristics such as absorption in particles, type of multipole resonance, and geometry of ensemble influence the convergence of Born series and its accuracy.

physics.optics↗

arXiv2021

Multipole optimization of light focusing by silicon nanosphere structures

We investigate the applicability of the coupled multipole model and its modification in the framework of the zero-order Born approximation for modeling of light focusing by finite-size nanostructures of silicon nanospheres, supporting electric and magnetic dipole and quadrupole resonances. The results based on the analytical approximations are verified by comparison with the numerical simulations performed by the T-matrix method. Using the evolutionary algorithm optimization, we apply the developed approach to design the silicon nanosphere metalenses with predefined focusing properties. The obtained results demonstrate a strong optimization potential of the suggested calculation scheme for engineering ultra-thin metalenses.

physics.optics↗

arXiv2020

High-Q localized states in finite arrays of subwavelength resonators

We introduce a novel physical mechanism for achieving giant quality factors ($Q$-factors) in finite-length periodic arrays of subwavelength optical resonators. The underlying physics is based on interference between the band-edge mode and another standing mode in the array, and the formation of spatially localized states with dramatically suppressed radiative losses. We demonstrate this concept for an array of $N$ dipoles with simultaneous cancellation of multipoles up to $N$-th order and the $Q$ factor growing as $Q \propto N^α$, where $α\gtrsim 6.88$. Based on this finding, we propose a realistic array of Mie-resonant nanoparticles ($N \lesssim 29$) with a dramatic enhancement of the Purcell factor (up to $\sim $3400) achieved by tuning of the array parameters.

physics.optics↗