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Three-dimensional light trap for reflective particles

United States Patent

5,939,716
August 17, 1999
View the Complete Patent at the US Patent & Trademark Office
Sandia National Laboratories - Visit the Intellectual Property Management and Licensing Website
A system for containing either a reflective particle or a particle having an index of refraction lower than that of the surrounding media in a three-dimensional light cage. A light beam from a single source illuminates an optics system and generates a set of at least three discrete focussed beams that emanate from a single exit aperture and focus on to a focal plane located close to the particle. The set of focal spots defines a ring that surrounds the particle. The set of focussed beams creates a "light cage" and circumscribes a zone of no light within which the particle lies. The surrounding beams apply constraining forces (created by radiation pressure) to the particle, thereby containing it in a three-dimensional force field trap. A diffractive element, such as an aperture multiplexed lens, or either a Dammann grating or phase element in combination with a focusing lens, may be used to generate the beams. A zoom lens may be used to adjust the size of the light cage, permitting particles of various sizes to be captured and contained.
Neal; Daniel R. (Tijeras, NM)
Sandia Corporation (Albuquerque, NM)
08/ 832,144
April 2, 1997
GOVERNMENT RIGHTS The Government has rights to this invention pursuant to Contract No. DE-AC04-94AL85000 awarded by the U.S. Department of Energy.