Status & Perspectives in Science & Education

71 70 Principal Scientist Profiles Maria Chernysheva Maria Chernysheva Principal Scientist Profiles MARIA CHERNYSHEVA RESEARCH AREAS The research of her group concentrates on the enhancement of ultrafast fibre laser technology. Specific focus is currently placed on: • Investigation of novel fast nonlinear modulating techniques and advanced broadband material saturable absorbers • Investigation of fundamentals of ultrashort pulse dynamics in laser cavities, for example, instability-driven phenomena or formation and interaction of ultrashort pulses • Research on novel soft-glass fibres, design of fibre-based components and fibre structures • Innovative laser sources at Short-wave and Mid-infrared wavelength regions TEACHING FIELDS Dr Chernysheva teaches a course on “Ultrafast Fiber Laser: Technology and Applications” for the M.Sc. Photonics and for the M.Sc. Physics. RESEARCH METHODS The Group of Ultrafast Fibre Lasers combines different techniques for the fabrication and characterisation of fibrebased laser components and resonators and ultrashort pulses in the wavelength range spanning from 1 to 5 µm: • Numerous laser sources, pump diodes and pulseshaping techniques • Dispersion Fourier transformation-based real-time spectral measurements, optical spectrum analysers • 33-GHz Digital storage oscilloscope, FROG and autocorrelations • Optical fibre post-processing and functionalisation JUNIOR RESEARCH GROUP LEADER FOR ULTRAFAST FIBER LASERS, LEIBNIZ INSTITUTE OF PHOTONIC TECHNOLOGY Maria Chernysheva studied laser physics at the Fiber Optics Research Center of the Russian Academy of Sciences and, since 2019, has been leading the Junior Research Group for Ultrafast Fiber Lasers, Leibniz Institute of Photonic Technology. Prior to this position, she worked as a Marie Skłodowska-Curie research fellow and Royal Academy of Engineering research fellow at Aston University, UK. Her main research direction has been nonlinear dynamics and new generation regimes in ultrafast fibre lasers. RECENT RESEARCH RESULTS One of the research directions of the group was focused on the interaction- and collisiondriven bidirectional generation of ultrashort pulses in ring mode-locked lasers. The results experimentally demonstrated a plethora of phenomena, such as the formation of synchronised and unsynchronised dispersion waves, Q-switched instabilities, and wavelength drift with the consequent pulse annihilation [1,2]. The developed bidirectional lasers offered the flexibility of the single laser system to generate a controllable dual-frequency comb. Its combination with real-time spectral acquisition techniques based on dispersive Fourier transformation opens up spectroscopy and rotation sensing applications, reaching phase retrieval of ~7 mrad at tens of MHz data acquisition rates [3]. Aiming to expand beneficial fibre optics platforms towards the Mid-IR wavelength range and enable shaping of the ultrashort dynamics, the group investigates unique soft-glass fibres, which feature drastically different material, thermal and chemical properties compared to conventional silica. The research activities, therefore, have included designing a full set of soft-glass fibre-based laser components, such as beam combiners operating via evanescence field interaction and fibre Bragg grating structures. Thus, the recent fundamental studies of fibre Bragg grating optical properties have paved the way to mastering the inscription process for individual soft-glass composition [4] and achieving controllable refractive index modification [5, 6]. BROADBAND TUNEABILITY AND ULTRASHORT PULSE GENERATION IN TMDOPED FIBRE LASER OMITTING FILTERS AND SATURABLE ABSORBERS The recent findings of the Ultrafast Fibre Lasers junior research group have confirmed the possibility of creating a Thulium-doped ultrafast fibre laser with a ~90 nm wavelength tuneability range around 1900 nm. The demonstrated concept is simple and elegant in two respects: neither a spectral filter nor a saturable absorber had to be applied as extra laser components. Precisely designed and controlled excitation dynamics of Thulium ions in active optical fibre solely guided the ultrashort pulse generation [7]. Such instabilities are generally considered parasitic, but their control and manipulation offer a new avenue of opportunities to establish tailored ultrafast generation. Figure: Experimental observation of real-time spectral evolution during ultrashort pulse formation in mode-locked fibre laser over a submicrosecond time span. [1] Kudelin et al. Photonics Research 8(6), 776-780 (2020). [2] Kudelin et al. Communication Physics 3(1) 202 (2020). [3] Kudelin et al. Advanced Photonics Research 3 (8), 2200092 (2022). [4] Chiamenti, Optics Letters 46(8), 1816-1819 (2021). [5] Ruepert et al. ACS Photonics 10(8) 2765–2773 (2023). [6] Becker, J. Lightwave Technol. 39, 2956-2960 (2021). [7] Kirsch et al. Communications Physics 5, 219 (2022). Contact: Phone: + 49 3641 206 312 Email: maria.chernysheva@leibniz-ipht.de Figure: Large angle light scattering on fibre Bragg gratings in soft-glass multimode fibres. Figure: Concept of the exploitation of rare-ions pair excitations for selfmode-locked ultrashort pulse generation in fibre lasers.

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