Description
Proposed by Landau in the 1940s [1], rotons are collective excitations in superfluid with relatively high momentum, compared to commonplace phonons. They are known to be responsible for the superfluid critical velocity, below which flow is unimpeded, illustrating their importance in superfluid behaviour. Optical generation of rotons was first achieved in 1969 using Raman scattering [2]. More recently, experiments have used femtosecond pulses and polarization manipulation to measure short time dynamics [3].
In this poster, I will outline our plans to probe the properties of roton generation using light, in confined geometries. One approach is to observe the roton signature in a hollow core fiber, which will offer an unmatched electric field confinement (due to the small mode diameter and long fiber length) in the bulk superfluid. Secondly, we will measure rotons using on-chip photonics and utilize the properties of optical cavities to generate and readout excitations. This will be made possible by creating high quality photonic chips via E-Beam Lithography. Upon demonstration of the control of rotons, we will investigate the applicability of our system to broader applications, for example the storage of quantum information.
References
[1]. Landau, L., 1941, Theory of the Superfluidity of Helium II. Physical Review, 60(4), p.356
[2]. Greytak, T.J. and Yan, J., 1969. Light scattering from rotons in liquid helium. Physical Review Letters, 22(19), p.987.
[3]. Milner, A.A., Stamp, P.C. and Milner, V., 2023. Ultrafast nonequilibrium dynamics of rotons in superfluid helium. Proceedings of the National Academy of Sciences, 120(17), p.e2303231120.
| I am the presenting author | Yes |
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