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Self-aligned Dual-Beam Optical Laser Trap Using Photorefractive Phase Conjugation

W. Wang, A.E. Chiou, G.J. Sonek, and M.W. Berns

In 1969, Ashkin demonstrated that two counter-propagating focused laser beams form a stable 3-D trap for small dielectric spheres (see Fig. 1a). In 1985, a stable single-beam gradient optical trap (see Fig. 1b) was successfully demonstrated. Since then, optical laser traps in both dual- and single-beam geometries have been developed and used extensively for sample micromanipulation and force transduction.