Strong Polarization Transformation of Bloch Surface Waves

Polarization is an intrinsic attribute of optical waves, so manipulating the polarization state of optical surface waves can be of fundamental importance for next-generation information and biophotonics technology. Here, we show theoretically that the polarization of the Bloch surface wave (BSW) on a dielectric multilayer can be transformed between a transverse-electric state and a transverse-magnetic state by using the laterally continuous grooves inscribed on this multilayer. This polarization transformation can be enhanced or inhibited by the interference between the reflected BSW beams, which can be tuned by the periodicity and depth of the grooves. Maximum polarization transformation efficiency can be achieved as high as 43% when the number of grooves is increased to ten. A generalized Fresnel formula is proposed to describe the polarization transformation of the BSW beams. Because of this polarization transformation, an anomalous reflection of BSW beams can be realized, which is the inequality between the incident angle and the reflection angle.