PT - JOURNAL ARTICLE
AU - Ballantine, Kyle E.
AU - Donegan, John F.
AU - Eastham, Paul R.
TI - There are many ways to spin a photon: Half-quantization of a total optical angular momentum
DP - 2016 Apr 29
TA - Science Advances
VI - 2
IP - 4
4099 - http://advances.sciencemag.org/content/2/4/e1501748.short
4100 - http://advances.sciencemag.org/content/2/4/e1501748.full
SO - Sci Adv2016 Apr 29; 2
AB - The angular momentum of light plays an important role in many areas, from optical trapping to quantum information. In the usual three-dimensional setting, the angular momentum quantum numbers of the photon are integers, in units of the Planck constant ħ. We show that, in reduced dimensions, photons can have a half-integer total angular momentum. We identify a new form of total angular momentum, carried by beams of light, comprising an unequal mixture of spin and orbital contributions. We demonstrate the half-integer quantization of this total angular momentum using noise measurements. We conclude that for light, as is known for electrons, reduced dimensionality allows new forms of quantization.