Abstract

Optical trapping technique, which uses a strongly focused laser beam¹⁾, has become an important tool for the precise manipulation of micrometer-sized particles such as polystyrene latex spheres²⁾ and biological cells³⁾. Almost the particles shown to be trapped are spheres, because the production of shape-controlled particles in micrometer range was quite difficult. Recently, mono-disperse hematite (α-Fe₂O₃) particles, of which both the shape and the size are simultaneously well-controlled, are produced by the gel-sol method⁴⁾. It has been revealed that several types of the particle shape, for example, pseudo-cubic and peanut-type, are obtainable. It is very interesting to apply these shape- and size-controlled particles to optical trapping and investigate the feature of the trapped particles. With regard to the micro structure fabrication, these mono-disperse particles are also attractive to use as model parts. We believe that the micro structure fabrication achieved by using optical trapping will be the basis of nanostructure fabrication because nanometer-sized particles, for example, 26 nm silica¹⁾ and 36 nm gold particles⁵⁾, have been demonstrated to be optically trapped.

© 1995 Optical Society of America