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

A super-length optical needle (~14λ) of strong transversally polarized field with homogeneous intensity along the optical axis and subdiffraction beam size (~0.9λ) 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.