径向偏振中空高斯光束的亚波长聚焦.doc


Sub-wavelength focusing generated by radially polarized
doughnut Gaussian beams#
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Jie Lin, Jian Guan, Jiubin Tan, Peng Jin*
(Center of Ultra-precision Optoelectronic Instrument, Harbin Institute of Technology, Harbin
150080)
Abstract: The radial polarized doughnut Gaussian beam is introduced firstly. The focusing
characteristics of radial polarized doughnut Gaussian beam by lens with high numerical aperture is
investigated based on Richards-Wolf's vectorial diffraction method. Numerical results indicates that
sub-wavelength focusing are obtained for incident radial polarized doughnut Gaussian beam. Therefore,
radial polarized doughnut Gaussian beam is considerable in the field of super-resolution
focusing.
Key words: Doughnut Gaussian beam; Diffraction theory; radially Polarization; subwavelength
focusing
0 Introduction
With the development of the field of micro/nano photonics, the requirements of the optical
elements with subwavelength feature size are urgent[1]. Therefore, the optical lithography system
and optical imaging system generally require smaller line width or optical super-resolution[2,3]. As
we known, diffraction occurs when propagation of light is perturbed. Based on Abbe's principle,
for an aplanatic imaging lens with numerical aperture NA, the focal spot size of plane light with
wavelength λ is limited by