Tuesday, April 06, 2004

First paper for Laser Tweezer

The principle of optical trapping was demonstrated in the 1980's with this paper published: A. Ashkin, J. M. Dziedzic, J. E. Bjorkholm and S. Chu, “Observation of a single beam gradient force optical tap for dielectric particles,” Opt. Lett. 11, 288, (1986)
The first optical traps were built by Arthur Ashkin at AT&T Bell Labs in the US in 1970. “Levitation traps” used the upward-pointing radiation pressure associated with a stream of photons to balance the downward pull of gravity,whereas “two-beam traps” relied on counter-propagating beams to trap particles.Then, in 1986, Ashkin and colleagues realized that the gradient force alone would be sufficient to trap small particles.They used a single tightly focused laser beam to trap a transparent particle in three dimensions. “Optical tweezers” had arrived in the laboratory.
K. Dholakia, G. Spalding and M. MacDonald, “Optical tweezers: the next generation,” Physics World 15-10
(October 2002)

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