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.

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We theoretically investigate the tight focusing properties of hybridly polarized vector beams. Some numerical results are obtained to illustrate the intensity, phase, and polarization of tightly focused hybridly polarized vector beams. It is shown that the shape of the focal pattern may change from an elliptical beam to a ring focus with increasing radial index. The phase distribution around the tightly focused ring is shown to be the helical phase profile, indicating that the radial-variant spin angular momentum of hybridly polarized vector beams can be converted into the radial-variant orbital angular momentum.

We investigate the intensity of a radially polarized power-exponent-phase vortex (PEPV) beam focused by a high-numerical-aperture objective. A bright focal spot and a focal annulus with a dark core can be generated by changing the phase of the PEPV beam. The possibility of trapping a gold particle with the bright focal spot and trapping an air bubble with the focal annulus is discussed, and the force and trapping stability are calculated. It is shown that a tightly focused radially polarized PEPV beam is applicable to trapping two types of particles.