Fully-structured light, light with non-uniform intensity, phase and polarization, lies at the heart of an extremely promising field of research, with applications in high-resolution imaging and optical trapping and manipulation of nanoparticles. Such fields are readily constructed from superpositions of two orthogonally polarized Laguerre-Gaussian modes carrying different orbital angular momentum (OAM). This opens new possibilities in engineering complex light distributions for specific applications.
We simulate the propagation of fully-structured light in a self-focusing nonlinear medium using a coupled two-dimensional nonlinear Schrödinger equation with saturable self-focusing nonlinearity and show that the spatial structure of the polarization can be used to control both the collapse dynamics of the beams  and the amount of polarisation rotation. These findings provide a novel approach to transport high-power light beams in nonlinear media with controllable distortions to their spatial structure and polarization properties.
Complex light can also have non-uniform helicity density and the resultant gradients in helicity density will generate a force that will interact differently with opposite enantiomers of chiral molecules . Here we demonstrate how the energy and helicity gradients in the fields, and the corresponding dipole and chiral forces, can be engineered for specific applications. We also investigate the use of nonlinearity to control and manipulate the spatially-varying chiral force.
 F. Bouchard et al., Phys. Rev. Lett 117, 233903 (2016)
 R. Cameron et al., New J. Phys. 16, 013020 (2014)
We have developed a new approach to measuring the spatial position of a single photon. Using fibers of different
length, all connected to a single detector allows us to use the high timing precision of single photon avalanche diodes
(SPAD) to spatially locate the photon. We have built two 8-element detector arrays to measure the full-field quantum
correlations in position, momentum and intermediate bases for photon pairs produced in parametric down conversion.
The strength of the position-momentum correlations is found to be an order of magnitude below the classical limit.
We demonstrate the use of holographic optical tweezers to form arrangements of silica beads for trapping and
measuring the mechanical properties of micron sized objects, such as oil droplets and yeast cells. This allows
us to investigate the mechanical properties of the constrained object, which need not be optically trapped itself
(thus preventing radiation damage and allowing objects with a low refractive index to be constrained). By
compressing the object with the beads we are able to determine the size of the trapped object and show that
there is an elastic coupling between the beads due to the presence of a trapped object. We expect more detailed
analysis of the system will allow mechanical and frequency-dependent viscoelastic properties of objects to be