title: Vectorial design of super-oscillatory lens.
abstract: A design and optimization method based on vectorial angular spectrum theory is proposed in this paper for the vectorial design of a super-oscillatory lens (SOL), so that the radially polarized vector beam can be tightly focused. The structure of a SOL is optimized using genetic algorithm and the computational process is accelerated using fast Hankel transform algorithm. The optimized results agree well with what is obtained using the vectorial Rayleigh-Sommerfeld diffraction integral. For an oil immersed SOL, a subwavelength focal spot of about 0.25 illumination wavelength without any significant side lobe can be created at a distance of 184.86 μm away from a large SOL with a diameter of 1mm. The proposed vectorial design method can be used to efficiently design a SOL of arbitrary size illuminated by various vector beams, with the subwavelength hotspot located in a post-evanescent observation plane.
authors.affiliation: Center of Ultra-precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin 150001, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.forename: Jiubin
authors.initials: J
authors.lastname: Tan
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Hongting
authors.initials: H
authors.lastname: Wang