The use of light with orbital angular momentum (OAM) is being investigated in a wide range of fields that include material interrogation, light propagation, sensing and communication1 . The defining characteristic of the electric field of OAM light is an angular term described by an azimuthal component such as e -imφ , which produces helical phasefronts and an angular momentum equal to mħ2 . For the cases where m ≠ 0 the beams can have an intensity minima along the central axis creating a beam of light which is tube-like in structure. This, together with the angular component of the energy flux, can cause the scattering interactions with materials to be different than that from plane waves. Theoretical angular scattering calculations show that the light scattering maxima can occur at different angles from the forward direction of zero degrees. In this work we investigate the scattering properties of OAM light from single, micron sized spherical particles that are suspended in a linear electrodynamic trap. Using phase plates we generate OAM beams (wavelength of 532 nm) that are incident on a single suspended particle. Using three separate CCDs we capture the scattered light intensity over a total range across 40 degrees in the forward, back and side scattering planes. Comparisons between angular scattering measurements from Gaussian beams and OAM mode equal to 3 is presented.
|