Our paper on optical binding in two-dimensions has been published as Xiang Han, Hui Luo, Guangzong Xiao and P. H. Jones. 'Optically bound colloidal lattices in evanescent optical fields', Optics Letters 41 4935 (2016).
From the abstract: In this Letter, we demonstrate the formation of a stable two-dimensional
lattice of colloidal particles in the interference pattern formed by
four evanescent optical fields at a dielectric interface. The
microspheres are observed to form a two-dimensional square lattice with
lattice vectors inclined relative to the beam propagation directions. We
use digital video microscopy and particle tracking to measure the
Brownian motion of particles bound in the lattice, and use this to
characterize fluctuations in the local ordering of particles using the
bond orientational order parameter, the probability distribution of
which is shown to be a chi-squared distribution. An explanation for the
form of this distribution is presented in terms of fluctuations of the
modes of a ring of particles connected by springs.