Polarization rotation of slow light with orbital angular momentum in ultracold atomic gases

Abstract

We consider the propagation of slow light with an orbital angular momentum (OAM) in a moving atomic medium. We have derived a general equation of motion and applied it in analysing propagation of slow light with an OAM in a rotating medium, such as a vortex lattice. We have shown that the OAM of slow light manifests itself in a rotation of the polarisation plane of linearly polarised light. To extract a pure rotational phase shift, we suggest to measure a difference in the angle of the polarisation plane rotation by two consecutive light beams with opposite OAM. The differential angle ∆α ℓ is proportional to the rotation frequency of the medium ωrot and the winding number ℓ of light, and is inversely proportional to the group velocity of light. For slow light the angle ∆α ℓ should be large enough to be detectable. The effect can be used as a tool for measuring the rotation frequency ωrot of the medium.

Slow polaritons with orbital angular momentum in atomic gases

“…The previous studies have concentrated on situations where the probe beam contains an OAM [41][42][43][44][45]. In the present paper we consider another scenario in which it is a control laser beam which can carry an optical vortex.…”

Electromagnetically induced transparency and nonlinear pulse propagation in a combined tripod and Λ atom-light coupling scheme

“…As illustrated in figure 4, the five-level tripod and Λ scheme is then equivalent to a conventional Λ-type atomic system [2,40] which is decoupled from the two-level system involving the states |B e and |e .…”

“…The former single-complonent slow light involves a probe beam of light and one or several control beams resonantly interacting with atomic media characterized by three level Lambda (Λ) type [2,40] or four level tripod type [41,42,[49][50][51] atom-light coupling schemes. In the later (spinor) case, double-tripod (DT) [6,[44][45][46][47][48] coupling schemes have been considered to support a simultaneous propagation of two probe beams leading to formation of a two-component slow light.…”

Angular spin-orbit coupling in cold atoms

“…Through the use of holographic techniques or spiral wave plates [12][13][14], far-field LG beams can now be created with relative ease. Manipulating cold atoms with LG beams has been studied both experimentally and theoretically, in the context of quantum information storage [15], slow light propagation [16], synthetic gauge fields [17], etc. The experiments that directly motivated our investigations [18,19] used LG beams to diabatically write phase windings and spin textures into a BEC, producing coreless vortices and Skyrmions in the process.…”