ORC Seminar Series

"Lights darkness"

Speaker: Professor Miles Padgett

Date: Wednesday 18 July 2007
Venue: Lecture Theatre B, Building 46, University of Southampton
Time: 2pm


Optical vortices and orbital angular momentum are currently topical subjects in the optics literature. Although seemingly esoteric they are in fact the generic state of light and arise whenever three or more plane waves interfere. To be observed by eye the light must be monochromatic and laser speckle is one such example, where the optical energy circulates around each black spot, giving a local orbital angular momentum.

This seminar will report three of our on-going studies. First, when considering a volume of interfering waves, the laser specs map out threads of complete darkness embedded in the light. Do these thread form loops? links? or even knots? Second, that when looking through a rapidly spinning window, the image of the world on the other side is rotated, true or false? Finally, that the entanglement of orbital angular momentum states means measuring the angular position of one photon sets the angular momentum of another - angular version of EPR?


Miles Padgett is Professor of Optics in the Department of Physics and Astronomy at the University of Glasgow. He heads a 15-man strong research team covering the full spectrum of blue-sky research to applied commercial development, funded by a combination of government, charity and industry. In 2001 he was elected to Fellowship of the Royal Society of Edinburgh.

Padgett has an international reputation for his contribution to the fundamental understanding of light's momentum, including conversion of optical tweezers into optical spanners, observation of a rotational form of the Doppler shift and a new form of Heisenberg's uncertainty principle. The applied aspects of his work have led to several commercial products and services, including a UV pollution monitor and a new technique for oil prospecting. Padgett's group has published over 150 papers that have amassed over 2000 citations in the world's leading scientific journals. He has made numerous TV, radio and popular press contributions and delivered many public lectures -- promoting science and technology to the widest possible audience.

Copyright University of Southampton 2006