title: Assembling of three-dimensional crystals by optical depletion force induced by a single focused laser beam.
abstract: We proposed a method to assemble microspheres into a three-dimensional crystal by utilizing the giant nonequilibrium depletion force produced by nanoparticles. Such assembling was demonstrated in a colloid formed by suitably mixing silica microspheres and magnetic nanoparticles. The giant nonequilibrium depletion force was generated by quickly driving magnetic nanoparticles out of the focusing region of a laser light through both optical force and thermophoresis. The thermophoretic binding of silica beads is so tight that a colloidal photonic crystal can be achieved after complete evaporation of solvent. This technique could be employed for fabrication of colloidal photonic crystals and molecular sieves.
authors.affiliation: Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China.
authors.forename: Hai-Dong
authors.initials: HD
authors.lastname: Deng
authors.forename: Guang-Can
authors.initials: GC
authors.lastname: Li
authors.forename: Hai-Ying
authors.initials: HY
authors.lastname: Liu
authors.forename: Qiao-Feng
authors.initials: QF
authors.lastname: Dai
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Wu
authors.forename: Sheng
authors.initials: S
authors.lastname: Lan
authors.forename: Achanta Venu
authors.initials: AV
authors.lastname: Gopal
authors.forename: Vyacheslav A
authors.initials: VA
authors.lastname: Trofimov
authors.forename: Tatiana M
authors.initials: TM
authors.lastname: Lysak
mesh_terms: D003460:Crystallization / Q000379:methods*; D007834:Lasers; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure*; D008422:Materials Testing; D012822:Silicon Dioxide / Q000737:chemistry* / Q000528:radiation effects; D013314:Stress, Mechanical
chemical_list: D058185:Magnetite Nanoparticles; D012822:Silicon Dioxide