arXiv subjects

Tetiana Slipchenko

Publications and source records attributed to Tetiana Slipchenko.

4 recordsLinked to original sources

arXiv2026

Enhanced Terahertz Photoresponse via Acoustic Plasmon Cavity Resonances in Scalable Graphene

Precise control and nanoscale confinement of terahertz (THz) fields are essential requirements for emerging applications in photonics, quantum technologies, wireless communications, and sensing. Here, we demonstrate a polaritonic cavity enhanced THz photoresponse in an antenna coupled device based on chemical vapor deposited (CVD) monolayer graphene. The dipole antenna lobes simultaneously serve as two gate electrodes, concentrate the impinging THz field, and efficiently launch acoustic graphene plasmons (AGPs), which drive a strong photo-thermoelectric (PTE) signal. Between 6 and 90 K, the photovoltage exhibits pronounced peaks, modulating the PTE response by up to 40\%, that we attribute to AGPs forming a Fabry Pérot THz cavity in the full or half graphene channel. Combined full wave and transport thermal simulations accurately reproduce the gate controlled plasmon wavelength, spatial absorption profile, and the resulting nonuniform electron heating responsible for the PTE response. The lateral and vertical maximum confinement factors of the AGP wavelength relative to the incident wavelength are 165 and 4000, respectively, for frequencies from 1.83 to 2.52 THz. These results demonstrate that wafer scalable CVD graphene, without hBN encapsulation, can host coherent AGP resonances and exhibit an efficient polaritonic enhanced photoresponse under appropriate gating, antenna coupling, and AGP cavity design, opening a route to scalable, polarization and frequency selective, liquid nitrogen cooled, and low power consumption THz detection platforms based on plasmon thermoelectric transduction.

cond-mat.mes-hall↗

arXiv2025

Tunable hyperbolic Landau-level polaritons in charge-neutral graphene nanoribbon metasurfaces

Magnetized charge-neutral graphene supports collective hybrid electronic excitations - polaritons - which have quantum origin. In contrast to polaritons in doped graphene, which arise from intraband electronic transitions, those in charge-neutral graphene originate from interband transitions between Landau levels, enabled by the applied magnetic field. Control of such quantum polaritons and shaping their wavefronts remains totally unexplored. Here we design an artificial two-dimensional quantum material formed by charge-neutral graphene nanoribbons exposed to an external magnetic field. In such metasurface, quantum polaritons acquire a hyperbolic dispersion. We find that the topology of the isofrequency curves of quantum hyperbolic magnetoexciton polaritons excited in this quantum material can change, so that the shape of isofrequency curves transforms from a closed to open one by tuning the external magnetic field strength. At the topological transition, we observe canalization phenomena, consisting of the propagation of all the polaritonic plane waves in the continuum along the same direction when excited by a point source. From a general perspective, our fundamental findings introduce a novel type of actively-tunable quantum polaritons with hyperbolic dispersion and can be further generalized to other types of quantum materials and polaritons in them. In practice, quantum hyperbolic polaritons can be used for applications related to quantum sensing and computing.

cond-mat.mes-hall↗

arXiv2025

Rough Fabry-Perot cavity: a vastly multi-scale numerical problem

A commercial Fabry-Perot laser diode is characterized by highly disproportionate dimensions, which poses a significant numerical challenge, even for state-of-the-art tools. This challenge is exacerbated when one of the cavity mirrors is rough-ened, as is the case when fabricating random laser diodes. Such a system involves length scales from several hundred mi-crometres (length) to a few nanometres (roughness) all of which are relevant when studying optical properties in the visi-ble. While involving an extreme range of dimensions, these cavities cannot be treated through statistical approaches such as those used with self-similar fractal structures known to show well-studied properties. Here we deploy numerical meth-ods to compute cavity modes and show how random corrugations of the Fabry-Perot cavity wall affect statistical proper-ties of their spectral features. Our study constitutes a necessary first step in developing technologically essential devices for photonic computation and efficient speckle-free illumination.

physics.optics↗

arXiv2020

Plasmonic antenna coupling to hyperbolic phonon-polaritons for sensitive and fast mid-infrared photodetection with graphene

Integrating and manipulating the nano-optoelectronic properties of Van der Waals heterostructures can enable unprecedented platforms for photodetection and sensing. The main challenge of infrared photodetectors is to funnel the light into a small nanoscale active area and efficiently convert it into an electrical signal. Here, we overcome all of those challenges in one device, by efficient coupling of a plasmonic antenna to hyperbolic phonon-polaritons in hexagonal-BN to highly concentrate mid-infrared light into a graphene pn-junction. We balance the interplay of the absorption, electrical and thermal conductivity of graphene via the device geometry. This novel approach yields remarkable device performance featuring room temperature high sensitivity (NEP of 82 pW-per-square-root-Hz) and fast rise time of 17 nanoseconds (setup-limited), among others, hence achieving a combination currently not present in the state-of-the-art graphene and commercial mid-infrared detectors. We also develop a multiphysics model that shows excellent quantitative agreement with our experimental results and reveals the different contributions to our photoresponse, thus paving the way for further improvement of these types of photodetectors even beyond mid-infrared range.

cond-mat.mes-hall↗