Generation of an axially super-resolved quasi-spherical focal spot using an amplitude-modulated radially polarized beam

Author(s): Han Lin, Baohua Jia, and Min Gu

Abstract:

“An axially super-resolved quasi-spherical focal spot can be generated by focusing an amplitude-modulated radially polarized beam through a high numerical aperture objective. A method based on the unique depolarization pro perties of a circular focus is proposed to design the amplitude modulation. The generated focal spot shows a ratio of x∶y∶z=1∶1∶1.48 for the normalized FWHM in three dimensions, compared to that of x∶y∶z=1∶0.74∶1.72 under linear polarization (in the x direction) illumination. Moreover, the focusable light efficiency of the designed amplitude-modulated beam is 65%, which is more than 3 times higher than the optimized case under linear polarization and thus make the amplitude-modulated radial polarization beam more suitable for a wide range of applications.”

Link to Publications Page

Publication: Optics Letters, (subscription required)

Issue/Year/DOI: Optics Letters, Vol. 36, Issue 13, pp. 2471-2473 (2011)
doi:10.1364/OL.36.002471