4-8 July 2016
Kramer Law building
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=10&confId=86">The Proceedings of SAIP2016</a> published on 24 December 2017

Quantum transport with vector beams

7 Jul 2016, 10:00
20m
5C (Kramer Law building)

5C

Kramer Law building

UCT Middle Campus Cape Town
Oral Presentation Track C - Photonics Photonics

Speaker

Mr Bienvenu Ndagano (University of the Witwatersrand)

Please indicate whether<br>this abstract may be<br>published online<br>(Yes / No)

Yes

Abstract content <br> &nbsp; (Max 300 words)<br><a href="http://events.saip.org.za/getFile.py/access?resId=0&materialId=0&confId=34" target="_blank">Formatting &<br>Special chars</a>

Using spatial modes of light is poised to be the next step in free-space bandwidth increase in point-to-point optical communication. Light carrying orbital angular momentum (OAM) is being extensively studied for this very purpose as it provides an additional degree of freedom that spans a discrete and infinite dimensional Hilbert space. As such, it would allow an infinite amount of information to be encoded on a photon. The propagation of spatial modes of light is however hindered by atmospheric turbulence which introduces random intermodal coupling, thereby affecting the fidelity of the detected signals. Here we propose a scheme in which vector vortex modes would be for communication instead of OAM modes. In vector vortex modes, the polarization and spatial degree of freedom are non-separable – a fundamental property of quantum entangled states. As the atmosphere is non-birefringent the polarization degree of freedom remains unaffected during propagation. We built an optical setup to generate and detect vector vortex modes using a q-plate. We simulate the atmospheric turbulence with the help of phase plate based on Kolmogorov’s theory of turbulence. We determined the intermodal coupling between four nearly degenerate vector modes as well as the energy transfer to higher order spatial modes as result of the turbulence plate. By evaluating the non-separability of the vector modes through a measurement of the concurrence, we showed that the polarization enhances the resilience of OAM modes to atmospheric turbulence.

Apply to be<br> considered for a student <br> &nbsp; award (Yes / No)?

Yes

Main supervisor (name and email)<br>and his / her institution

Andrew Forbes
andrew.forbes@wits.ac.za
University of the Witwatersrand

Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?

No

Level for award<br>&nbsp;(Hons, MSc, <br> &nbsp; PhD, N/A)?

MSc

Primary author

Mr Bienvenu Ndagano (University of the Witwatersrand)

Co-authors

Prof. Andrew Forbes (University of the Witwatersrand) Mr Benjamin Perez-Garcia (Photonics and Mathematical Optics Group, Tecnológico de Monterrey) Dr Carmelo Rosales-Guzman (University of the Witwatersrand) Dr Melanie McLaren (University of the Witwatersrand) Prof. Thomas Konrad (UKZN) Dr Yingwen Zhang (CSIR National Laser Centre)

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