title: Laser Trapping and Crystallization Dynamics of l-Phenylalanine at Solution Surface.
abstract: We present laser trapping behavior of l-phenylalanine (l-Phe) at a surface of its unsaturated aqueous solution by a focused continuous-wave (CW) near-infrared (NIR) laser beam. Upon the irradiation into the solution surface, laser trapping of the liquid-like clusters is induced concurrently with local laser heating, forming an anhydrous plate-like crystal at the focal spot. The following laser irradiation into a central part of the plate-like crystal leads to laser trapping at the crystal surface not only for l-Phe molecules/clusters but also for polystyrene (PS) particles. The particles are closely packed at crystal edges despite that the crystal surface is not illuminated by the laser directly. The molecules/clusters are also gathered and adsorbed to the crystal surface, leading to crystal growth. The trapping dynamics and mechanism are discussed in view of optical potential formed at the crystal surface by light propagation inside the crystal.
authors.affiliation: Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University , Hsinchu 30010, Taiwan.
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Yuyama
authors.affiliation: Instrument Technology Research Center, National Applied Research Laboratories , Hsinchu 30076, Taiwan.
authors.forename: Teruki
authors.initials: T
authors.lastname: Sugiyama
authors.affiliation: Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University , Hsinchu 30010, Taiwan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Masuhara
keywords: crystal surface; l-phenylalanine; laser trapping; light propagation; solution surface