Author Affiliations

Sonja Franke-Arnold,¹ Graham Gibson,¹ Robert W Boyd,^1,* and Miles J Padgett^1,†

¹School of Physics and Astronomy, SUPA, University of Glasgow, Glasgow, G12 8QQ, UK

^*Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5 Canada and The Institute of Optics and Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627, USA

^† m.padgett@physics.gla.ac.uk