Print Email Facebook Twitter Experimental demonstration of an intensity minimum at the focus of a laser beam created by spatial coherence: Application to the optical trapping of dielectric particles Title Experimental demonstration of an intensity minimum at the focus of a laser beam created by spatial coherence: Application to the optical trapping of dielectric particles Author Raghunathan, S.B. Van Dijk, T. Peterman, E.J.G. Visser, T.D. Faculty Electrical Engineering, Mathematics and Computer Science Department Telecommunications Date 2010-12-13 Abstract In trying to manipulate the intensity distribution of a focused field, one typically uses amplitude or phase masks. Here we explore an approach, namely, varying the state of spatial coherence of the incident field. We experimentally demonstrate that the focusing of a Bessel-correlated beam produces an intensity minimum at the geometric focus rather than a maximum. By varying the spatial coherence width of the field, which can be achieved by merely changing the size of an iris, it is possible to change this minimum into a maximum in a continuous manner. This method can be used, for example, in novel optical trapping schemes, to selectively manipulate particles with either a low or high index of refraction. To reference this document use: http://resolver.tudelft.nl/uuid:1a460aca-0a0f-4da8-aa74-c444987fcf55 DOI https://doi.org/10.1364/OL.35.004166 Publisher Optical Society of America ISSN 0146-9592 Source http://www.opticsinfobase.org/ol/abstract.cfm?URI=ol-35-24-4166 Source Optics Letters, 35 (24), 2010 Part of collection Institutional Repository Document type journal article Rights (c) 2010 Optical Society of America Files PDF Raghunathan_2010.pdf 429.71 KB Close viewer /islandora/object/uuid:1a460aca-0a0f-4da8-aa74-c444987fcf55/datastream/OBJ/view