Summer semester 2024
Organiser: Uwe Bandelow
Research seminar "Mathematical Models of Photonics"
Enrollment to the seminar: Students who want to attend this seminar for the modules P27, P28 and P35.3 should write an email to uwe.bandelow@hu-berlin.de. Please write as subject MathPho, your name, enrollment number, course of study.
I will save the email address and use it to send information regarding the seminar if this is not explicitly objected. You can cancel your enrollment to the seminar via email as well.
Proposed seminars
Thursday 04.04. 2024, 16:00 (WIAS-ESH)Prof. Dmitry Turaev. Imperial College London, UKWednesday 26.06.2024, 11:00 (WIAS Library (Hausvogteilplatz 5-7, 4th floor))
4-winged Lorenz attractors
We show that bifurcations of periodic orbits with multipliers (-1,i,-i) can lead to the birth of pseudohyperbolic Lorenz-like attractors of three different types: one is a discrete analogue of the classical Lorenz attractor, and the other two are new: two- and four-winged Simo angels. These three attractors exist in an orientation-reversing, three-dimensional, quadratic Henon map. This implies the abundance of such attractors in a class of systems with homoclinic tangencies. Our analysis is based on the study of a normal form for this bifurcation, a slow-fast three-dimensional system of differential equations with a Z4-symmetry. The existence of the continuous-time counterparts of the pseudohyperbolic attractors is established for the normal form as a part of an extensive numerical analysis of its bifurcations. In particular, we establish that all three types of continuous-time pseudohyperbolic attractors are born out of a certain Z4-symmetric heteroclinic configurations with three saddles.
Jasper Riebesehl, Technical University of DenmarkThursday 04.07.2024, 16:00 (WIAS-ESH)
Kalman filtering for noise characterization in optical frequency combs
This talk will explore a novel framework for digital characterization of phase noise in lasers and optical frequency combs, highlighting advantages over traditional analog methods. Key points include:
• Application of the extended Kalman filter (EKF) as a near-optimal phase estimator for accurate phase noise measurements amidst measurement noise.
• Joint processing of multiple comb lines to extract phase noise correlations.
• Application of automatic differentiation and adaptive optimization techniques to optimize high-dimensional state-space models.
• Demonstrations through simulations and experimental data, showcasing the framework’s effectiveness across various optical frequency combs and dual-comb measurements.
• Discussion on digital phase noise compensation, particularly relevant for free-running dual-comb spectroscopy applications.
Thursday 11.07.2024, 16:00 (WIAS-ESH)
Thursday 18.07.2024, 16:00 (WIAS-ESH)
Thursday 25.07.2024, 16:00 (WIAS-ESH)
Thursday 01.08.2024, 16:00 (WIAS-ESH)
Thursday 08.08. 2024, 16:00 (WIAS-ESH)
Thursday 15.08.2024, 16:00 (WIAS-ESH)
Thursday 22.08.2024, 16:00 (WIAS-ESH)
Thursday 29.08.2024, 16:00 (WIAS-ESH)
Thursday 05.09.2024, 16:00 (WIAS-ESH)
Thursday 19.09.2024, 16:00 (WIAS-ESH)
Thursday 26.09.2024, 16:00 (WIAS-ESH)