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Thursday, October 7, 2010

A Prototype Optical Tweezer System Employing Adaptive Optics Technology

R. Nash; S. Bowman; C. Bradley; R. Conan

This article describes the design, implementation and characterization of a novel optical tweezer system. The system utilizes a deformable mirror, wavefront sensor and controller to manipulate an optically trapped micro-particle within a small chamber. This method for optical trapping employs technology adopted from astronomical instrumentation; in particular, adaptive optics. A deformable mirror is employed to control the wavefront phase of a laser beam before it is imaged into a chamber by a high numerical aperture microscope objective lens. The wavefront phase is measured by a Shack-Hartman wavefront sensor and the particle's position monitored by a video camera. The goals of the work presented here are to trap particles ranging in size from 1 μm to 10 μm; create a suitable controller for moving trapped particles in three dimensions; image the trapped particle; determine the prototype system's performance specifications; and determine the trap stiffness.

DOI

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