We are a team of young and enthusiastic scientists interested in various aspects of wave physics, ranging from novel quantum optics effects to the theory of acoustomechanics. As part of the Department of Physics at ITMO University, we provide high-quality education and training through cutting-edge research at the top international level.
The group is supported by the Academic Leadership Program Priority 2030 grant "Pi Group: Scientific Hyperjump Initiative"
We investigate second-harmonic generation (SHG) in structured germanium nanohelices, breaking the inversion symmetry. Special spiral structuring enhances SHG over 100 times compared to nonstructured germanium. The study reveal how nonlinear circular dichroism, observed through SHG anisotropy, is affected by the handedness and density of the helices. Notably, altering the distance between neighboring helices reverses the sign of the anisotropy coefficient.
We propose a method to enhance the lifetime of double excitations in quantum emitter ensembles by suppressing radiative emission. Using the Friedrich-Wintgen mechanism of external coupling, similar to the formation of bound states in the continuum, we predict the generation of entangled photon pairs with non-zero angular momentum from quantum rings.
It turns out that an elegant condition (eq. 17) describes all possible symmetries of the nanoparticles and their crystalline lattices, harmonic orders, and angular momenta of vortex beams. In turn, another simple condition (eq. 105) outlines all possible cases when excited by vector beams. Despite the simplicity of the answer, various nuances arise in the process of deriving it, which are detailed in the paper.
This study examines all-optical light control via enhanced thermo-optical nonlinearity and optical bistability in a dielectric metasurface membrane with bound states in the continuum (BIC). By tuning radiative losses and adjusting the incidence angle, we demonstrate control over BIC resonance quality, hysteresis parameters, and transitions from bistability to optical discrimination. These findings highlight applications in optical switching and modulation with flat optics.
In this paper, we demonstrated a nonlinear metal-semiconductor nanostructure with a static electric field created at the interface between its component charge carriers generated by femtosecond laser radiation. Controlling the excitation mode allowed us to influence the presence of the static electric field and modify the second harmonic generation, which in the future opens the way to all-optical control of the output radiation and ultra-fast logic transitions in a single nanoantenna.
In order to advance the development of quantum emitter-based devices, it is essential to enhance light-matter interactions through coupling between semiconductor quantum dots with high quality factor resonators. In our new paper, efficient tuning of the emission properties of HgTe quantum dots in the infrared spectral region is demonstrated by coupling them to a plasmonic metasurface that supports bound states in the continuum
New article about the group leader Mikhail Petrov and the group's projects!
Quantum emitters coupled to waveguides experience long-range interactions mediated by photons, leading to to superradiant and subradiant states, photon bound states, etc. This article by Alexandra Sheremet et al. reviews a wide range of such systems and their description by theoretical methods and insights from different fields of physics.
When does nonlinear circular dichroism appear in achiral dielectric nanoparticles?
The paper by Anastasia Nikitina, Anna Nikolaeva and Kristina Frizyuk give an answer and a simple formula for Cnh and Dnh nanoparticle symmetries and any possible χ² materials
Congratulations to Kristina Frizyuk!
New outlook at the bianosotropy of the meta-atoms from the symmetry point of view from master student Mariia Poleva with Kristina Frizyuk, Kseniia Baryshnykova, Mihail Petrov, and Andrey Bogdanov. We extend the classical definition of bianisotropy to the case of higher-order multipoles and make a connection between classical and multipolar definitions of bianisotropy.
Congratulations to Ivan Toftul!
Choose your fighter: disorder or asymmetric coupling, battlefield: 1D quantum atomic array. In our recent paper published in Physics Review A Gleb Fedorovich, Danil Kornovan, Alexander Poddubny and Mihail Petrov revealed the competition between these two phenomena in the formation of localized and delocalized states.
We report photonic crystal structures as a tool for optomechanical pulling/pushing regimes switching in narrow spectral regions. The results are applicable for precise sorting of resonant nanoparticles with good tolerance to the resonant wavelengths.
Another result of the long standing collaboration with Prof. Rachel Grange, Dr. Maria Timofeeva, and Dr. Elizaveta Semenova has been accepted to Nanoscale journal. We propose controlling of the nonlinear optical signal generation via mechanical stretching of the semiconductor metaarrays.
See also: ONG website at ETH Zurich
How to classify the mode of acoustic resonator in terms of group theory and multipole content? The recent paper by our 3rd year Bachelor students Maria Tsimoha, Valdimir Igoshin, and Anastasia Nikitina was published in Physical Reviews B journal. Many thanks to Kristina Frizyuk and Ivan Toftul for supervision of the project.
by Vladimir Igoshin, Anastasiya Nikitina, Mariia Tsimokha
