The Department of Physics is delighted to welcome Professor Alessia Pasquazi (Loughborough University) as a Colloquium Speaker for the academic year 2025/26. Please join us to listen to Professor Pasquazi's seminar.
A reception will be held directly after the seminar in 8 West 3.15, where tea and coffee will be provided.
The seminar is open to anyone from the university, students are encouraged to attend.
Title
Laser cavity solitons in microcombs: dynamics, robustness, and perspectives
Abstract
Optical frequency combs in microresonators, or microcombs, are coherent optical sources composed of equally spaced spectral lines generated by Kerr nonlinearity. The discovery of dissipative temporal cavity solitons marked a turning point, enabling broadband, smooth comb spectra ideally suited for metrology and precision timing.
We demonstrated that localized pulses can self-organize when a nonlinear microresonator is nested within a fibre laser loop, leading to the formation of laser cavity solitons. This architecture merges the robustness of laser cavities with the compactness of microresonators, providing an intrinsic route for the creation, stabilization, and control of solitary waves in integrated photonic platforms.
Our recent work has shown that these solitons can spontaneously emerge, persist, and self-recover even after strong perturbations, highlighting their dissipative resilience and topological protection mechanisms. In particular, the interplay between fast Kerr dynamics and slow nonlinearities—such as gain saturation and thermal feedback—governs a topological bifurcation structure that locks the soliton’s repetition rate and phase.
In this talk, I will discuss how these effects establish noise-quenched and topologically constrained states that extend the operational stability of microcombs toward fully free-running, metrology-grade sources. The discussion will integrate both experimental evidence and the underlying mathematical model linking modal symmetry, topology, and soliton attractor dynamics.
References
[1] H. Bao, et al. Laser Cavity-Soliton Microcombs. Nat. Photonics 13, 384 (2019).
[2] M. Rowley,. et al. Self-emergence of robust solitons in a microcavity. Nature 608, 303–309 (2022).
[3] A. Cutrona, et al. Nonlocal bonding of a soliton and a blue-detuned state in a microcomb laser. Commun Phys 6, 259 (2023).
Biography
Prof. Alessia Pasquazi received her PhD in Engineering from the University of Roma Tre in 2009. She was a MELS Fellow in Québec, Canada (2010–2011), a Marie Skłodowska-Curie Fellow (2013–2015), and held an Ernest Rutherford Fellowship (2018–2022). She is currently an ERC Starting Grant Laureate (2020–2025).
Her research focuses on nonlinear photonics and microcombs, with particular emphasis on ultrafast dynamics, topological soliton states, and integrated photonic platforms. Prof. Pasquazi led pioneering work in ultrafast integrated optics at the EPic Lab, University of Sussex (2014–2022), and now directs the Emergent Photonics Research Centre (EPicX) at Loughborough University.
She is an active contributor to the international photonics community, regularly serving on program committees and chairs for SPIE, OPTICA, and IEEE conferences. Notably, she was General Chair of the OSA Nonlinear Photonics Conference (2018, 2020) and currently serves as Program Chair for CLEO-Europe/EQEC 2025.