All-Optically Tunable Goos-Hanchen Shift Owing To The Microstructure Transition Of Ferrofluid In A Symmetrical Metal-Cladding Waveguide

We report on the observation of all-optically tunable Goos-Hanchen (GH) shift in a symmetrical metal-cladding waveguide, whose guiding layer is filled with the water-based ferrofluid. The strong dependence of the GH shift and its switching time on the control beam power is suggested to be arising from the light-induced periodic-like microstructure transitions of ferrofluid in virtue of the competition between the optical trapping effect and the Soret effect. The indirect evidence of our qualitative hypothesis is given. The presented tunability of GH shift may have potential applications in optical switching and sensing. (C) 2013 AIP Publishing LLC.