Tight Focusing of Double-ring-shaped Azimuthally Polarized Beam Using High NA Lens Axicon
J. Environ. Nanotechnol., Volume 3, No (Special Issue) (August 2014) pp. 39-42
Abstract
The intensity distribution in the focal region for the double-ring-shaped azimuthally polarized beam using high NA lens axicon system is studied on the basis of the vector diffraction theory. A method is presented for generation of a sub wavelength (0.5 λ) azimuthally polarized beam, which propagates without divergence over lengths of about (60.8 λ) in free space. It is also observed that the distribution of the electric field does not change while the aberration coefficient of the lens axicon changes. The authors expect such a super-long dark channel may find applications in optical data storage, biomedical imaging, laser drilling and atmospheric sciences.
