Multimode Cavity Optomechanics in superfluid Helium droplets*

The “minimal” optomechanical system consists in an optical cavity with a vibrating end mirror. There is, in this case, one optical mode coupled via radiation-pressure force to one mechanical mode [1].
Recently, it was proposed a novel optomechanical system based upon millimeter-size droplets of liquid Helium magnetically levitated in vacuum where the droplet serves both as optical and mechanical resonator [2]. The optical resonances are given by the whispering-gallery modes of light and the mechanical resonances by the vibrational surface modes. These about 10³ resonances ranges from 2π x 23 Hz to 2π x 219 kHz [3].
In this presentation we illustrate the principal unusual characteristics of the multimode dynamics [4] of the optically excited Helium droplet and we present some preliminary results about nonlinear effects.


[1] M. Aspelmeyer, T. J. Kippenberg and F. Marquardt, Rev. Mod. Phys 86, 1391 (2014).
[2] L. Childress et al., Phys. Rev. A 96, 063842 (2017).
[3] A. Aiello, J. Harris and F. Marquardt, arXiv:1809.02640 [physics.optics] (2018).
[4] H. Seok et al., Phys. Rev. A 88, 063850 (2013).