Orbital momentum of light

It has been known since the middle ages that light exerts a radiation pressure. Not so well known is that light also exerts a twist.

The intricate nature of this twist was not recognised until the 1990s and we have been working on it ever since. Beyond the fascination of setting microscopic objects into rotation, this orbital angular momentum may hold the key to better communication sensing and imaging systems. 

Orbital Angular Momentum (OAM)

The phase fronts of light beams in orbital angular momentum (OAM) eigenstates rotate, clockwise for positive OAM values, anti-clockwise for negative values. The phase front with 0 OAM doesn't rotate at all.

OAM = -1 hbar per photon (right-hand
helical phase front)
OAM = 0
(plane wave)
OAM = +1 hbar per
photon (left-hand helix)
OAM = +2 hbar
per photon
(two-fold helix)
OAM = +3 hbar
per photon
(three-fold helix: fusilli) 

PhD opportunities

We are happy to discuss a PhD proposal that is of interest to you and aligned to our own scientific ambitions. Feel free to get in touch.

Prof Miles Padgett

Selected publications

  • G. C. G. Berkhout, M. P. J. Lavery, J. Courtial, M. W. Beijersbergen, and M. J. Padgett, Efficient Sorting of Orbital Angular Momentum States of Light, Phys. Rev. Lett. 105, 153601 (2010), doi: 10.1103/PhysRevLett.105.153601
  • S. Franke-Arnold, G. Gibson, R. W. Boyd and M. J. Padgett, Rotary Photon Drag Enhanced by a Slow-Light Medium, Science 333, 65-67 (2011), doi: 10.1126/science.1203984
  • A. M. Yao and M. J. Padgett, Orbital angular momentum: origins, behavior and applications, Adv. Opt. Photon. 3, 161-204 (2011), doi: 10.1364/AOP.3.000161
  • M. R. Dennis, R. P. King, B. Jack, K. O'Holleran, and M. J. Padgett, Isolated optical vortex knots, Nature Phys. 6, 118-121 (2010), doi: 10.1038/NPHYS1504