title: Refractive elements for the measurement of the orbital angular momentum of a single photon.
abstract: We have developed a mode transformer comprising two custom refractive optical elements which convert orbital angular momentum states into transverse momentum states. This transformation allows for an efficient measurement of the orbital angular momentum content of an input light beam. We characterise the channel capacity of the system for 50 input modes, giving a maximum value of 3.46 bits per photon. Using an electron multiplying CCD (EMCCD) camera with a laser source attenuated such that on average there is less than one photon present within the system per measurement period, we demonstrate that the elements are efficient for the use in single photon experiments.
authors.affiliation: School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK. m.lavery@physics.gla.ac.uk
authors.forename: Martin P J
authors.initials: MP
authors.lastname: Lavery
authors.forename: David J
authors.initials: DJ
authors.lastname: Robertson
authors.forename: Gregorius C G
authors.initials: GC
authors.lastname: Berkhout
authors.forename: Gordon D
authors.initials: GD
authors.lastname: Love
authors.forename: Miles J
authors.initials: MJ
authors.lastname: Padgett
authors.forename: Johannes
authors.initials: J
authors.lastname: Courtial
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007909:Lenses; D008027:Light; D008029:Lighting / Q000295:instrumentation*; D008962:Models, Theoretical; D017785:Photons; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation