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

Date

2019年2月12日 (火) 14:00

Location

D014, Level D, Lab 1

Description

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)

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