Roman S. Savelev

Large-area and high-spatial-resolution photodetectors with the ability of light direction recognition have promising application prospects in smart sensors, human−machine interaction, the Internet of Things, and other fields. However, current photodetectors often fail to achieve accurate direction recognition of light and require a trade-off between high spatial resolution and device size. Here, we show a printed microscale perovskite dual-line structure designed for resonant, directionally selective absorption, which creates differentiated photocurrents under visible light from different directions. After investigating the change of reflected light from the eyeball, a single dual-line microstructure can be integrated as a wearable photodetector for monitoring eye movement abnormalities. The frequency and amplitude of eye movement can be recorded for early warning of neurological disorders and monitoring nervous system diseases. This strategy provides a new approach for creating high-performance optoelectronic devices using printed photonic resonant structures, which extends the application of optoelectronic devices in brain science.

Dielectric metawaveguides that leverage the resonant behavior of individual dielectric scatterers have recently been suggested as a versatile platform for controlling light propagation and tailoring light–matter interactions in integrated optical circuits. Their broad tunability is of particular interest for the realization of various reconfigurable optical elements. Here, we propose an approach for realizing optical isolation based on a metawaveguide composed of silicon nanoparticles exhibiting a predominant in-plane electric dipole response. We show that perturbation of the metawaveguide geometry leads to the formation of modes with a non-zero transverse optical spin through the mode coupling mechanism. Furthermore, by incorporating magnetic material into the waveguide, we demonstrate a compact optical isolator compatible with the silicon-on-insulator platform and provide a general framework for its design. Our results have significant implications for the advancement of high-density photonic circuits and may enable functionalities in directional emission, optical communications, and sensing technologies.

The local polarization of the electromagnetic field plays a crucial role in the interaction of light with spin- and valley-polarized quantum sources. Unlike free-space electromagnetic waves, whose polarization degeneracy enables flexible polarization manipulation, planar integrated optical structures lack such degree of freedom owing to intrinsic structural anisotropy. Here, we propose a planar optical ring resonator based on a subwavelength grating waveguide that supports two quasi-degenerate modes. We demonstrate that coupling of these modes in the ring resonator leads to the formation of the resonances with a predominant direction of electric-field rotation in the vicinity of the resonator, resulting in the non-zero transverse optical spin. The average degree of circular polarization in the proposed structures reaches values of up to 70%. The theoretical predictions are corroborated by experimental validation in the microwave spectral range. Our findings suggest a viable route toward realization of on-chip optical spintronic and valleytronic interfaces.

We propose and numerically investigate a novel compact planar microcavity design based on a high-index dielectric slab waveguide with an embedded monolayer semiconductor. Compared to more traditional vertical Bragg microcavities, our design relies on the transmission of guided optical modes and achieves strong exciton–photon coupling in a chip-compatible and compact geometry with sub-100 nm thickness. We show that Rabi splitting values of more than 70 meV can be obtained in planar microcavities with a total length below 5 μ m . Further, we reveal the dependence of Rabi splitting on the dimensions of the structure and explain it with a simple theoretical model. Our results contribute towards the development of novel compact 2D semiconductor-based components for integrated photonic circuits.

Arrays of coupled dipole emitters support collective single- and multiphoton states that can preserve quantum excitations. One of the crucial characteristics of these states is the lifetime, which is fundamentally limited due to spontaneous emission. Here, we present a mechanism of the external coupling of two states via the radiation continuum, which allows for an increase in the lifetime of both single and double excitations. As an illustrative example, we consider a ringlike ensemble of quantum emitters, demonstrating that upon slight optimization of the structure geometry, one can increase the lifetime of singly and doubly excited states with nonzero orbital momentum by several orders of magnitude. The proposed mechanism of multiphoton excitations lifetime control has a universal nature and might be applied for a wide class of open quantum systems and quantum ensembles besides the particular geometry considered in this Letter.

Suppressing the spontaneous emission in quantum emitters ensembles (atoms) is one of the topical problems in quantum optics and quantum technology. While many approaches are based on utilizing the subradiance effect in ordered quantum emitters arrays, the ensemble configurations providing the minimal spontaneous emission rate are yet unknown. In this work, we employ the differential evolution algorithm to identify the optimal configurations of a few atomic ensembles that support quantum states with maximal radiative lifetime. We demonstrate that atoms tend to assemble mostly in quasi-regular structures with specific geometry, which strongly depends on the minimally allowed interatomic distance rmin. While the discovered specific non-radiative realizations of small ensembles cannot be immediately predicted, there is particular correspondence to the non-radiative states in the atomic lattices. In particular, we have found that states inheriting their properties either from the bound states in the continuum or band edge states of infinite lattices dominate across a wide range of rmin values. Additionally, we show that for small interatomic distances, the linear arrays with modulated spacing have the smallest radiative losses exponentially decreasing as the size of the ensemble increases.