Abstract

The principles of the single-beam gradient force optical trap are considered. Laser trapping and manipulation of individual sub-micron colloids, viruses, and bacteria have been observed for the first time. Light scattering measurements were made from single particles and fixed arrays of particles. Methods of measuring particle size and orientation are discussed. Optical separation of individual particles is possible. The single-beam gradient trap operates over a range of 10⁵ in particle size. Its use opens much of the submicron Rayleigh size range to optical trapping manipulation.

© 1986 Optical Society of America