Microwave-induced orbital angular momentum transfer

Abstract

The microwave-induced orbital angular momentum (OAM) transfer from a Laguerre-Gaussian (LG) beam to a weak plane-wave is studied in a closed-loop four-level ladder-type atomic system. The analytical investigation shows that the generated fourth field is an LG beam with the same OAM of the applied LG field. Moreover, the microwave-induced subluminal generated pulse can be switched to the superluminal one only by changing the relative phase of applied fields. It is shown that the OAM transfer in subluminal regime is accompanied by a slightly absorption, however, it switches to the slightly gain in superluminal regime. The transfer of light’s OAM and control of the group velocity of the generated pulse can prepare a high-dimensional Hilbert space which has a major role in quantum communication and information processing.

Identifying orbital angular momentum of light in quantum wells

“…According to the above results, we may conclude that the number of lobes and the rotation of the pattern can be useful as a detector of the azimuthal index of vortex fields. What is noticeable, and which deserves to be highlighted, is that such identifications are obviously different from those in studies on the transfer of the OAM of light which were worked out in atomic ensembles [49][50][51]. Here, the probe beam does not acquire any vortices from pump fields with a well-defined OAM; instead, its absorption profile can reflect azimuthal phase variation of those fields, mainly due to obtaining some OAM components from such fields with LG modes.…”

Azimuthal modulation of probe absorption and transfer of optical vortices

“…Here we are going to mention that several systems have been reported where the vortices present in the control field have been transferred to probe light beam. Such transferred of optical vortices have been observed in atomic systems [35][36][37][38][39][40], semiconductor quantum dots [41] and semiconductor quantum wells [42,43].…”

Highly efficient exchange of orbital angular momentum of light via electron spin coherence

“…The interaction of optical vortex light carrying orbital angular momentum (OAM) with the atomic system has recently been observed [28][29][30][31][32][33][34][35]. An optical vortex is a beam that has an optical phase that depends on the azimuthal coordinate and a wavefront that is helical.…”