"Knotted optical vortices and polarisation structures and their interaction with matter waves" Simon Gardiner, Durham University, UK

Speaker

Prof. Simon Gardiner
Deputy Head of the Faculty of Science (Undergraduate), Durham University, UK
Associate Director of the Joint Quantum Centre (JQC) Durham-Newcastle

Abstract

Following seminal theoretical [1,2] and experimental [3-5] work on constructing knotted optical vortices in laser light in the paraxial approximation we have studied the creation of knotted ultracold matter waves in atomic Bose–Einstein condensates via two- photon Raman transitions [6] as well as the creation of knotted structures in the longitudinal polarization component of light beyond the paraxial approximation [7]. The Raman transition allows an indirect transfer of atoms from the internal state |a⟩ to the target state |b⟩ via an excited state |e⟩. This enables us to imprint 3D knotted vortex lines embedded in the probe field to the target state density . We have illustrated our approach to structure the longitudinal polarisation component of light by demonstrating linked and knotted longitudinal vortex lines acquired upon nonparaxially propagating a tightly focused subwave-length beam . We note that the remaining degrees of freedom in the transverse polarization components can be exploited to generate customized topological vector beams.

[1] M.V. Berry, M.R. Dennis
Knotted and linked phase singularities in monochromatic waves
Proc. R. Soc. Lond. A 457 2251 (2001)
[2] M.V. Berry, M.R. Dennis
Knotting and unknotting of phase singularities: Helmholtz waves paraxial waves and waves in 2 + 1 dimensions
J. Phys. A: Math. Gen. 34 8877 (2001 )
[3] J. Leach, M.R. Dennis, J. Courtial, M.J. Padgett
Knotted threads of darkness
Nature 432 165 (2004)
[4] J. Leach, M.R. Dennis, J. Courtial, M.J. Padgett
Vortex knots in light
New J. Phys. 7 55 (2005)
[5] M.R. Dennis, R.P. King, B. Jack, K. O’Holleran, M.J. Padgett
Isolated optical vortex knots
Nat. Phys. 6 118 (2010)
[6] F. Maucher, S.A. Gardiner, I.G. Hughes,
Excitation of knotted vortex lines in matter waves
New J. Phys. 18 063016 (2016)
[7] F. Maucher, S. Skupin, S.A. Gardiner, I.G. Hughes
Creating complex optical longitudinal polarization structures
Phys. Rev. Lett. 120 163903 (2018)