  Photonic hooks (PHs) are non-evanescent light beams with a highly
concentrated curved optical fields. Since their discovery, PHs always have one
single inflection point and thus have a hook-like structure. In this work, a
new type of PHs with two inflection points and S-shaped structures (S-PHs) were
reported for the first time. We theoretically studied the effects of various
physical parameters on the generation of S-PHs. Furthermore, we showed that
decorating particles with multiple patches can significantly enhance the
curvature and length of the S-PHs. The S-PHs may have potential applications in
super-resolution imaging, sub-wavelength micromachining, particle and cell
manipulation, etc.
