Giant non-specular effects at the interface of Bloch surface wave structures

The interference of reflections and refractions in a periodical dielectric structure generates a surface electromagnetic wave named Bloch surface wave. The absence of ohmic losses renders the Bloch surface wave strongly enhance the non-specular effect, like the Goos-Hanchen shift, with low optical loss. In that case, giant non-specular effect induced by the Bloch-surface-wave is easy to observe. Here the spatial phase distribution is experimentally measured as well as the intensity distribution. Experiments reveal that the non-specular reflection could lead to strong spatial phase variation across the beam profile besides the intensity distortion. This discovery helps better understanding of the physical process of the non-specular reflection, and the observed giant non-specular effect provides potential applications involving high performance optical sensors.