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X-WR-CALNAME:UNAM Nanoteknoloji Araştırma Merkezi
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X-WR-CALDESC:Events for UNAM Nanoteknoloji Araştırma Merkezi
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DTSTART:20240101T000000
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DTSTART;TZID=Europe/Moscow:20241030T110000
DTEND;TZID=Europe/Moscow:20241030T123000
DTSTAMP:20260906T093149
CREATED:20241023T070015Z
LAST-MODIFIED:20241023T070015Z
UID:9121-1730286000-1730291400@unam.bilkent.edu.tr
SUMMARY:Nonlinear dynamics and chaos in multimode semiconductor lasers
DESCRIPTION:Stefan Bittner\nUniversity of Lorraine \n\nNonlinear dynamics and chaos in multimode semiconductor lasers \nNonlinear dynamics and deterministic chaos are ubiquitous in nature and appear in a large variety of physical\, chemical and biological systems. Due to their strong nonlinearities\, lasers exhibit a very wide range of different dynamics and are ideal testbeds for studying chaotic dynamics. Interest in laser dynamics has been renewed due to emerging applications of ultrafast chaotic dynamics like chaos cryptography\, physical random number generation\, sensing applications like chaotic LIDAR or information processing and reservoir computing [1]. Semiconductor lasers are ideal for realizing chaos-based applications thanks to their ultrafast dynamics\, compact size and low energy consumption. \nIn the first part of the talk\, we present the experimental investigation of a free-running broad-area VCSEL (vertical cavity surface emitting laser) [2]. We observe mode competition between lasing modes with different spatial patterns and polarizations. Time-domain measurements of the laser emission show irregular fluctuations\, and we use methods from time-series analysis to confirm that the VCSEL exhibits chaotic dynamics in certain parameter regimes. Such lasers with intrinsic chaotic dynamics are promising candidates for applications like chaos cryptography. \nIn the second part of the talk\, the detailed investigation of an edge-emitting broad-area laser is presented [3]. Time-domain heterodyning measurements enable us to obtain the spectrum of the laser with ultra-high resolution. In addition to the expected transverse modes of order 1 to 8\, we find that multiplets of 1st and 2nd order transverse modes are created by the nonlinear dynamics. We demonstrate that the modes in these multiplets are phase-locked\, which is unexpected for a broad-area laser without external perturbation or control. The coexistence of synchronized (phase-locked) modes and unsynchronized ones is similar to so-called chimera states found in networks of coupled oscillators [4] which also exhibit partial synchronization and are found in various physical\, chemical and biological systems. \n\nHigh resolution spatio-spectral image of a broad-area semiconductor laser pumped high above threshold. The frequencies and the spatial profiles of transverse modes of order 1 to 8 are revealed. \n[1] Sciamanna & Shore\, “Physics and applications of laser diode chaos”\, Nature Photonics 9\, 151 (2015)\n[2] Bittner & Sciamanna\, “Complex nonlinear dynamics of polarization and transverse modes in a broad-area VCSEL”\, APL Phot. 7\, 126108 (2022)\n[3] Bittner & Sciamanna\, “Spontaneous phase locking in a broad-area semiconductor laser”\, arXiv:2405.07268 (2024)\n[4] Abrams & Strogatz\, “Chimera States for Coupled Oscillators”\, Phys. Rev. Lett. 93\, 174102 (2004) \n  \n  \n  \n  \nKonuşmacı hakkında\nPhD thesis 2007-2010 at Technical University Darmstadt (Germany)\nPostdoc 2010-2012 at TU Darmstadt\n2012-2014 Postdoc at ENS Cachan (France)\n2015-2018 Research Scientist at Yale University\, Department of Applied Physics\n2019-2024 Research Scientist at CentraleSupélec\, laboratory LMOPS (laboratory for optical materials\, photonics and systems) in Metz\, France\nSince September 2019: Associate Professor (Maître de Conférences) at University of Lorraine\, laboratory LMOPS in Metz\, France \n  \n \n  \n\n  \n 
URL:https://unam.bilkent.edu.tr/en/event/nonlinear-dynamics-and-chaos-in-multimode-semiconductor-lasers/
CATEGORIES:Nanocolloquium Series
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