We report the formation of optically tunable, smooth hollow beams by reflection of a TEM<sub>00</sub> Gaussian beam off a metal thin film. Hollow (doughnutlike) beams (HBs) with controllable profiles are created by a phase distortion at the surface. Two regimes of operation are observed: Below a certain power threshold, the HB formation is reversible and optically tunable on a time scale of milliseconds; above that threshold, alterations on the film surface make the effect permanent. Optical control of the HB shape is demonstrated by tuning the power of a second beam. High stability in the radial intensity profile and the possibility of adjusting the spatial distribution and aspect ratios make this technique promising for applications such as atom trapping and manipulation of Bose-Einstein condensates.
© 2006 Optical Society of America
Optics at Surfaces
Original Manuscript: November 17, 2005
Revised Manuscript: March 27, 2006
Manuscript Accepted: April 25, 2006
Irina Gerdova, Xinhui Zhang, and Alain Haché, "Optically tunable hollow Gaussian beams with thin metal films," J. Opt. Soc. Am. B 23, 1934-1937 (2006)