Giant positive and negative Goos-Hanchen shift on dielectric gratings caused by guided mode resonance

Giant positive and negative Goos-Hanchen shift more than 5000 times of the operating wavelength is observed when a beam is totally reflected from a substrate decorated by a dielectric grating. Different to the former studies where Goos-Hanchen shift is related to metamaterials or plasmonic materials with ohmic loss, here the giant shift is realized with unity reflectance without the loss. This is extremely advantageous for sensor applications. The Goos-Hanchen shift exhibits a strong resonant feature at the frequency of guided mode resonance, and is associated to the energy flow carried by the guided mode.