Generation of super-length optical needle by focusing hybridly polarized vector beams through a dielectric interface

A super-length optical needle (similar to 14 lambda) of strong transversally polarized field with homogeneous intensity along the optical axis and subdiffraction beam size (similar to 0.9 lambda) can be generated by focusing a hybridly polarized vector beam through a dielectric interface with an annular high-NA lens. Moreover, it is found that the polarization of the cross section near the focal plane is radial variant. Such a nondiffracting optical needle may have applications in atom-optical experiments, such as with atom trap and atom switches. (C) 2012 Optical Society of America