You are cordially invited to UNAM Nanocolloquium seminars focusing on advancements in the field of nanoscience and nanotechnology. The seminars bring us the most recent developments in these exciting fields. This week\u2019s talk will be presented by Prof. Stefan Bittner (University of Lorraine).<\/p>\n
Nanocolloquium series<\/p>\n
Title: Nonlinear dynamics and chaos in multimode semiconductor lasers<\/p>\n
Date: October 30, 2024 (Wednesday)
\nTime and Venue: 11:00 UNAM Conference Hall (SU-01)<\/p>\n
Abstract:
\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.<\/p>\n
In 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.<\/p>\n
In 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.<\/p>\n[1] Sciamanna & Shore, \u201cPhysics and applications of laser diode chaos\u201d, Nature Photonics 9, 151 (2015) [2] Bittner & Sciamanna, \u201cComplex nonlinear dynamics of polarization and transverse modes in a broad-area VCSEL\u201d, APL Phot. 7, 126108 (2022) [3] Bittner & Sciamanna, \u201cSpontaneous phase locking in a broad-area semiconductor laser\u201d, arXiv:2405.07268 (2024) [4] Abrams & Strogatz, \u201cChimera States for Coupled Oscillators\u201d, Phys. Rev. Lett. 93, 174102 (2004)<\/p>\n
Short Bio:
\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 CentraleSup\u00e9lec, laboratory LMOPS (laboratory for optical materials, photonics and systems) in Metz, France
\nSince September 2019: Associate Professor (Ma\u00eetre de Conf\u00e9rences) at University of Lorraine, laboratory LMOPS in Metz, France<\/p>\n","protected":false},"excerpt":{"rendered":"
You are cordially invited to UNAM Nanocolloquium seminars focusing on advancements in the field of nanoscience and nanotechnology. The seminars bring us the most recent developments in these exciting fields. This week\u2019s talk will be presented by Prof. Stefan Bittner (University of Lorraine). Nanocolloquium series Title: Nonlinear dynamics and chaos [\u2026] <\/p>\n