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Physics Seminar

Exploring fundamental light-matter interactions with thermo-refractive noise in nanophotonic waveguides

Speaker: Prof. Nicolas Le Thomas (University of Ghent-IMEC)
Date: Wednesday 18 November 2020
Time: 15:00
Venue: Zoom

I will discuss the origin of an unexpected thermo-refractive noise contribution that we recently identified in nanophotonic waveguides made of amorphous materials [1]. This noise that corresponds to dynamic fluctuations in the picosecond time range sets a fundamental detection limit in photonic integrated circuits, in particular in integrated Raman sensor. Beyond the implications for sensing applications, the presence of this noise is a direct experimental signature of irreversible thermodynamic effects where inertia phenomena cannot be ignored. It also highlights the limits of current theories of thermo-refractive noise at high frequencies. Moreover, the possibility of experimentally accessing the optical spectrum of this noise contribution could be an opportunity to improve our understanding of optical non-linear effects in the presence of dissipation and go beyond models that ignore memory effects.

[1] N. Le Thomas, A. Dhakal, A. Raza, F. Peyskens, R. Baets, “Impact of fundamental thermodynamic fluctuations on light propagating in photonic waveguides made of amorphous materials”, Optica 5, 328-326 (2018).