Highly birefringent vaterite microspheres: production, characterization and applications for optical micromanipulation.
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.
Parkin
Simon J
SJ
University of Queensland, School of Mathematics and Physics, Queensland, Australia.
Vogel
Robert
R
Persson
Martin
M
Funk
Maren
M
Loke
Vincent L Y
VL
Nieminen
Timo A
TA
Heckenberg
Norman R
NR
Rubinsztein-Dunlop
Halina
H
D016880:Anisotropy; D001718:Birefringence; D004867:Equipment Design; D007834:Lasers; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008863:Microspheres; D053758:Nanoparticles; D036103:Nanotechnology / Q000379:methods; D055095:Optics and Photonics; D010316:Particle Size; D014961:X-Ray Diffraction