Focusing And Manipulating Of The Vectorial Field Based On Optical Antenna

As the carrier of information,the basic elements of light,such as the frequency,amplitude and phase,have been studied deeply and the relevant technologies have been applied in various fields.Recently,the characteristics and manipulation of the polarized states of the light attracted more and more attentions.Many researchers have made effort to investigate the vectorial field which with space-variant polarized states,especially the manipulating and strong focusing of this light.The focused field has potential applications in laser machining,particle trapping,optical data storage and optical microscopy and so on.Based on the focusing and manipulating of vectorial field,we analyzed focusing characteristics of vectorial field under high numerical aperture.In this paper,we analyzed the focusing characteristics of vectorial field under high numerical aperture by utilizing the reversal radiation of the dipole array.Then we investigated a discrete pupil filter for complex amplitude through engineering the metasurface with subwavelength optical antenna array.By combining of the reversing radiation theory of electric-magnetic dipole antenna and Richards-Wolf Vector diffraction integral theory,we created a three-dimensional volume chain under a high numerical aperture objective lens obeying the sine condition.We give a procedure to The structure of the chain can be modulated freely by changing the initial phase difference,amplitude ratio,adjacent space and the radiation of the electric-magnetic dipole array.The incident field at the pupil plane also was obtained by reversing radiation of the dipole array.Compared with the focused field before,this dipolar-shaped focus field will meet potential applications in multiple particles trapping,delivering and self-assembling.According to the similarity between the slot antenna and linear polarizer,a metasurface with multiple subwavelength slot antenna arrays with different directions is investigated.As a discrete pupil filter for complex amplitude,this metasurface can be used to tailor the incident laser filed.Then the filtered filed can be focused into special vectorial focal filed.The slot antenna can manipulate the amplitude and phase locally.And every ring has its own transmittance and binary phase shift(0/?).As an example,the incident radial polarized light passes through this filter and focused by a high numerical aperture lens.Then the diffraction-limited ultra-long three-dimensional optical tube can be obtained in the focal region.This type of metasurface can guide us to find a new way for the generation and manipulation of the vectorial filed.