Eur. Phys. J. D 64, 103-108 (2011)
https://doi.org/10.1140/epjd/e2011-10703-6

Regular Article

Subwavelength dark hollow focus of spirally polarized axisymmetric Bessel-modulated Gaussian beam

¹ Electronics and Information College, Hangzhou Dianzi University, Hangzhou 310018, P.R. China
² Shanghai Key Laboratory of Modern Optics System, University of shanghai for Science and Technology, Shanghai 200093, P.R. China
³ China Standard Software Co., Ltd, Shanghai 200030, P.R. China
⁴ College of Physics Science, Qingdao University, Qingdao 266071, P.R. China

^a e-mail: xiumingao@yahoo.com.cn

Received: 11 December 2010
Received in final form: 26 April 2011
Published online: 29 July 2011

Abstract

Dark hollow focus plays an important role in many optical systems. In this paper, dark hollow focal shaping of spirally polarized axisymmetric Bessel-modulated Gaussian beam is investigated by vector diffraction theory in detail. Results show that the dark hollow focus can be altered considerably by beam parameter and spiral parameter that indicates polarization spiral degree. One dark hollow focus and two dark hollow foci pattern may occur for certain spiral parameter, and the transverse size of dark hollow focus can be less than the diffraction limit size of bright focus. In addition, there may also appear two triangle dark hollow foci that are connected by one dark line focus.