title: Tuning and Freezing Disorder in Photonic Crystals using Percolation Lithography.
abstract: Although common in biological systems, synthetic self-assembly routes to complex 3D photonic structures with tailored degrees of disorder remain elusive. Here we show how liquids can be used to finely control disorder in porous 3D photonic crystals, leading to complex and hierarchical geometries. In these optofluidic crystals, dynamically tunable disorder is superimposed onto the periodic optical structure through partial wetting or evaporation. In both cases, macroscopic symmetry breaking is driven by subtle sub-wavelength variations in the pore geometry. These variations direct site-selective infiltration of liquids through capillary interactions. Incorporating cross-linkable resins into our liquids, we developed methods to freeze in place the filling patterns at arbitrary degrees of partial wetting and intermediate stages of drying. These percolation lithography techniques produced permanent photonic structures with adjustable disorder. By coupling strong changes in optical properties to subtle differences in fluid behavior, optofluidic crystals may also prove useful in rapid analysis of liquids.
authors.affiliation: Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario Canada.|Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA.
authors.forename: Ian B
authors.initials: IB
authors.lastname: Burgess
authors.affiliation: John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
authors.forename: Navid
authors.initials: N
authors.lastname: Abedzadeh
authors.affiliation: Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA.|John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
authors.forename: Theresa M
authors.initials: TM
authors.lastname: Kay
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
authors.forename: Anna V
authors.initials: AV
authors.lastname: Shneidman
authors.affiliation: John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Cranshaw
authors.affiliation: John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
authors.forename: Marko
authors.initials: M
authors.lastname: Lončar
authors.affiliation: Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA.|John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.|Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.|Kavli Institute for Bionano Sciences and Technology, Harvard University, Cambridge, MA, USA.
authors.forename: Joanna
authors.initials: J
authors.lastname: Aizenberg