Abstract: Optical tweezers was invented by an American scientist Arthur Ashkin in 1986. It is mainly used to manipulate micro-particles and used as a transducer of tiny force. As the technique of optical tweezers develops, it makes large contribution to the research of the manipulation of biological macromolecules and the mechanism in the vital process of macromolecules. The working principle of optical tweezers is introduced in this article, and the process of constructing a low cost optical tweezers system with the present apparatus in our lab is present here. We also observe the capture of several kinds of particles. And it turns out that the optical tweezers has an efficient range and the capability of trap decreases when the size of the particle increases.

Key words: optical tweezers, light pressure, gradient force, optical trap, particle, capture