title: Polarization independence of laser-induced nucleation in supersaturated aqueous urea solutions.
abstract: In a seminal report on laser-induced nucleation in aqueous supersaturated solutions (Phys. Rev. Lett., 1996, 77, 3475) it was noted that needle-shaped crystals of urea were aligned with the direction of the electric field of the linearly polarized laser pulse. The results gave rise to a new mechanism for control of crystal nucleation involving alignment of solute molecules (optical Kerr effect) now commonly known as non-photochemical laser-induced nucleation (NPLIN). Recent theoretical and experimental work has cast doubts on the optical Kerr effect mechanism. In the present letter we present results from digital imaging of urea-crystal growth immediately following laser-induced nucleation. Analysis of the data shows no statistically significant correlation between crystal angle and direction of linear polarization. The results overturn a long-held result that has shaped theoretical and experimental studies of NPLIN.
authors.affiliation: School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh, Scotland EH9 3FJ, UK. andrew.alexander@ed.ac.uk.
authors.forename: Yao
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh, Scotland EH9 3FJ, UK. andrew.alexander@ed.ac.uk.
authors.forename: Martin R
authors.initials: MR
authors.lastname: Ward
authors.affiliation: School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh, Scotland EH9 3FJ, UK. andrew.alexander@ed.ac.uk.
authors.forename: Andrew J
authors.identifier: http://orcid.org/0000-0002-0897-020X
authors.initials: AJ
authors.lastname: Alexander