Highly birefringent vaterite microspheres: production, characterization and applications for optical micromanipulation

• Published in: Optics express Vol. 17; no. 24; pp. 21944 - 21955
• Main Authors: Parkin, Simon J, Vogel, Robert, Persson, Martin, Funk, Maren, Loke, Vincent L Y, Nieminen, Timo A, Heckenberg, Norman R, Rubinsztein-Dunlop, Halina
• Format: Journal Article
• Language: English
• Published: United States 23-11-2009
• Subjects: Anisotropy; AQUEOUS-SOLUTION; Atom and Molecular Physics and Optics; Atom- och molekylfysik och optik; Birefringence; CACO3; CALCIUM-CARBONATE; CRYSTAL-GROWTH; Equipment Design; FORCE; HYDROPHILIC BLOCK-COPOLYMERS; KINETICS; Lasers; MICROPARTICLES; Microscopy, Electron, Scanning - methods; Microscopy, Electron, Transmission - methods; Microspheres; Nanoparticles; Nanotechnology - methods; Optics and Photonics; Particle Size; PRECIPITATION; TWEEZERS; X-Ray Diffraction
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/oe.17.021944

This paper reports on a simple synthesis and characterization of highly birefringent vaterite microspheres, which are composed of 20-30 nm sized nanocrystalls. Scanning electron microscopy shows a quite disordered assembly of nanocrystals within the microspheres. However, using optical tweezers, the effective birefringence of the microspheres was measured to be Deltan = 0.06, which compares to Deltan = 0.1 of vaterite single crystals. This suggests a very high orientation of the nanocrystals within the microspheres. A hyperbolic model of the direction of the optical axis throughout the vaterite spherulite best fits the experimental data. Results from polarized light microscopy further confirm the hyperbolic model.