ORCID Profile
0000-0002-2058-5320
Current Organisation
Uniwersytet Warszawski
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Publisher: American Physical Society (APS)
Date: 25-08-2021
Publisher: American Physical Society (APS)
Date: 10-03-2023
Publisher: American Physical Society (APS)
Date: 22-05-2022
Publisher: Optica Publishing Group
Date: 16-02-2021
Abstract: Multicomponent Bose–Einstein condensates, quantum Hall systems, and chiral magnetic materials display twists and knots in the continuous symmetries of their order parameters known as skyrmions. Originally discovered as solutions to the nonlinear sigma model in quantum field theory, these vectorial excitations are quantified by a topological winding number dictating their interactions and global properties of the host system. Here, we report the experimental observation of a stable in idual second-order meron and antimeron appearing in an electromagnetic field. We realize these complex textures by confining light into a liquid-crystal-filled cavity that, through its anisotropic refractive index, provides an adjustable artificial photonic gauge field that couples the cavity photon motion to its polarization, resulting in the formation of these fundamental vectorial vortex states of light. Our observations could help bring topologically robust room-temperature optical vector textures into the field of photonic information processing and storage.
Publisher: Wiley
Date: 30-09-2022
Abstract: This paper introduces a new approach to neuromorphic photonics in which microcavities exhibiting strong exciton–photon interaction may serve as building blocks of optical spiking neurons. The experimental results demonstrate the intrinsic property of exciton–polaritons to resemble the Leaky Integrate‐and‐Fire (LIF) spiking mechanism. It is shown that exciton–polariton microcavities when non‐resonantly pumped with a pulsed laser exhibit leaky integration due to relaxation of the excitonic reservoir, threshold‐and‐fire mechanism due to transition to Bose–Einstein Condensate (BEC), and resetting due to stimulated emission of photons. These effects, evidenced in photoluminescence characteristics, arise within sub‐ns timescales. The presented approach provides means for ultrafast processing of spike‐like laser pulses with energy efficiency at the level below 1 pJ per spike.
Publisher: American Chemical Society (ACS)
Date: 26-02-2021
Publisher: AIP Publishing
Date: 04-2023
DOI: 10.1063/5.0136380
Abstract: Exciton–polaritons in optical cavities exhibit strong nonlinearities predominantly because of the third-order Kerr-like interactions mediated by the excitonic component. Under quasi-resonant excitation, depending on the energy of the incident laser, it results in the optical limiting or bistable behavior. The latter phenomenon is manifested by the hysteresis loop observed in the input–output power characteristics, when a cavity is quasi-resonantly driven by a laser field. The direction of the loop is typically counterclockwise when increasing and subsequently decreasing the optical power. In this work, we demonstrate the optical bistability with an inverted hysteresis direction. It is observed in an exfoliated CdTe-based semiconductor microcavity when the frequency of the pumping laser is tuned slightly below the lower polariton mode. This unusual behavior is caused by the interplay of the suppression of strong coupling and the redshift of the lower polariton mode energy when increasing the incident power. We show that under these conditions, the polariton microcavity can be used as an optical limiter. All of the experimental observations, the shape and the direction of the hysteresis and the optical limiting behavior, are fully supported by a theoretical model.
No related grants have been discovered for Krzysztof Tyszka.