Generation of a sub-diffraction hollow ring by shaping an azimuthally polarized wave.

ABSTRACT: The generation of a sub-diffraction optical hollow ring is of great interest in various applications, such as optical microscopy, optical tweezers, and nanolithography. Azimuthally polarized light is a good candidate for creating an optical hollow ring structure. Various of methods have been proposed theoretically for generation of sub-wavelength hollow ring by focusing azimuthally polarized light, but without experimental demonstrations, especially for sub-diffraction focusing. Super-oscillation is a promising approach for shaping sub-diffraction optical focusing. In this paper, a planar sub-diffraction diffractive lens is proposed, which has an ultra-long focal length of 600?? and small numerical aperture of 0.64. A sub-diffraction hollow ring is experimentally created by shaping an azimuthally polarized wave. The full-width-at-half-maximum of the hollow ring is 0.61??, which is smaller than the lens diffraction limit 0.78??, and the observed largest sidelobe intensity is only 10% of the peak intensity.

SUBMITTER: Chen G 

PROVIDER: S-EPMC5120339 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature