Abstract

It has been an increasingly active area to use light, in the form of an optical trap, to manipulate microsphere objects without physical contact. In biology, an optical trap provides a new and novel tool for the manipulation of microorganisms and cells with great precision. Ashkin and his colleagues first discovered that dielectric objects as a micrometer sized cell or bacterium could be trapped by a single laser beam with this simple technique.¹ Various biological objects, including viruses, bacteria, yeast cells, and red blood cells, have been trapped successfully by using a cw laser in the configuration of single-beam gradient force optical trap,^2-4 and, recently, a related theoretical model has been developed to predict the trapping forces.⁵

© 1992 Optical Society of America