arXiv subjects

Krzysztof Tyszka

Publications and source records attributed to Krzysztof Tyszka.

5 recordsLinked to original sources

arXiv2026

Image recognition based on optical spike processing with exciton-polaritons

Exciton-polariton condensates combine ultrafast dynamics with strong optical nonlinearities, making them promising for optical neuromorphic computing. Here, we numerically demonstrate image recognition using the transient response of an exciton-polariton condensate. Downscaled MNIST images are encoded as optical pulse sequences, and the resulting condensate dynamics are sampled and processed by a linear classifier. For ten-class classification, condensate features achieve 92.2% accuracy, compared with 91.4% for raw-pixel linear classification. Combining both feature sets increases the accuracy to 93.2%. For the challenging binary classification of digits 7 and 9, the combined model reaches 97.3%, exceeding both the linear (95.5%) and feed-forward neural-network (96.6%) baselines. These results demonstrate that polariton dynamics can extract useful nonlinear features for ultrafast optical information processing.

physics.optics↗

arXiv2025

Guided polariton condensate in perovskite microwires

Perovskite microwires are promising candidates for integrated photonic systems due to their strong nonlinear optical response and inherent waveguiding capabilities. In this study, we focus on the directional emission properties of exciton-polariton condensates formed within perovskite microwires, with emphasis on emission collected from the microwire end. We constructed a multi-angle optical detection setup that allows us to identify the exciton-polariton condensation threshold and track the evolution of the condensate for different excitation position along and across the microwire. We observe spectrally narrow exciton-polariton condensate emission from the microwire end even when the condensate is generated tens of micrometers away, which demonstrates the ability of the exciton-polariton condensate to propagate over long distances within the microwire. Furthermore, we find that the presence of structural defects near the condensate location can significantly enhance the emission from the microwire end due to aligning the condensate's momentum with the waveguide direction, thereby facilitating more efficient propagation.

physics.optics↗

arXiv2024

Room temperature exciton-polariton neural network with perovskite crystal

Limitations of electronics have stimulated the search for novel unconventional computing platforms that enable energy-efficient and ultra-fast information processing. Among various systems, exciton-polaritons stand out as promising candidates for the realization of optical neuromorphic devices. This is due to their unique hybrid light-matter properties, resulting in strong optical nonlinearity and excellent transport capabilities. However, previous implementations of polariton neural networks have been restricted to cryogenic temperatures, limiting their practical applications. In this work, using non-equillibrium Bose-Einstein condensation in a monocrystalline perovskite waveguide, we demonstrate the first room-temperature exciton-polariton neural network. Its performance is verified in various machine learning tasks, including binary classification, and object detection. Our result is a crucial milestone in the development of practical applications of polariton neural networks and provides new perspectives for optical computing accelerators based on perovskites.

physics.optics↗

arXiv2023

Natural exceptional points in the excitation spectrum of a light-matter system

We observe natural exceptional points in the excitation spectrum of an exciton-polariton system by optically tuning the light-matter interactions. The observed exceptional points do not require any spatial or polarization degrees of freedom and result solely from the transition from weak to strong light-matter coupling. We demonstrate that they do not coincide with the threshold for photon lasing, confirming previous theoretical predictions [Phys. Rev. Lett. 122, 185301 (2019), Optica 7, 1015 (2020) ]. Using a technique where a strong coherent laser pump induces up-converted excitations, we encircle the exceptional point in the parameter space of coupling strength and particle momentum. Our method of local optical control of light-matter coupling paves the way to investigation of fundamental phenomena including dissipative phase transitions and non-Hermitian topological states.

physics.optics↗

arXiv2022

Neural networks based on ultrafast time-delayed effects in exciton-polaritons

We demonstrate that time-delayed nonlinear effects in exciton-polaritons can be used to construct neural networks where information is coded in optical pulses arriving consecutively on the sample. The highly nonlinear effects are induced by time-dependent interactions with the excitonic reservoir. These nonlinearities allow to create a nonlinear XOR logic gate that can perform operations on the picosecond timescale. An optoelectronic neural network based on the constructed logic gate performs classification of spoken digits with a high accuracy rate.

physics.optics↗