Speaker： Daniele Sanvitto
Director of Research at the Institute of Nanotechnology of the Italian National Research Council (CNR)
Time： 14:00-15:00 Jan 10 (wednesday) 2024
Polaritons, hybrid quasiparticles arising from the strong interaction between photons and electronic excited states in materials, have
become a focal point of research due to their intriguing properties. In the seminar we will explore the interaction of polaritons with
topology, [1] emphasizing recent progress in tailoring their band structures. [2] The manipulation of symmetry-mismatched resonant
polariton modes, leading to the creation of topologically protected bound states in the continuum (BICs), will be discussed. These BICs,
with theoretically infinite lifetimes, open up new possibilities for polariton states, showcasing the potential for ultra-low threshold
Bose-Einstein condensation.
We will see the advantages of using 2D planar waveguides to tailor band topologies offering ease of growing and external control,
leading to an increase of interaction via dipolar effects. [3,4] The discussion will delve into the intriguing possibility of patterning these
waveguides through shallow or deep etching, unlocking avenues for realising topologically protected polariton modes [5]. Furthermore,
by harnessing the effective attractive potential stemming from the negative mass of these states, we will show the prospect of achieving
optical self-trapping. This concept paves the way for the implementation of evanescent coupling—rather than ballistic—among multiple
polariton condensates. [6]
[1] A. Gianfrate, et al., Measurement of the quantum geometric tensor and of the anomalous Hall drift. Nature 578, 381 (2020).
[2] L. Polimeno, et al. Tuning the Berry curvature in 2D Perovskite polaritons. Nat. Nanotech., Nature Nanotechnol. 16, 1349 (2021).
[3] D. G. Suárez-Forero, et al., Electrically controlled waveguide polariton laser. Optica 7, 1579 (2020).
[4] D. G. Suárez-Forero, et al., Enhancement of parametric effects in polariton waveguides induced by dipolar interactions. Physical
Review Letters, 126, 137401 (2021).
[5] V. Ardizzone, et al., Polariton Bose-Einstein condensate from a bound state in the
continuum. Nature 605, 447 (2022).
[6] A. Gianfrate, et al., Reconfigurable quantum fluid molecules of bound states in the continuum. Nature Physics (2024)
