Abstract
We present a design method of four-quadrant pure phase filter and phase modulation functions for creating two focusing spots. With the combination of a high numerical aperture objective and a four-quadrant pure phase filter, a radially polarized incident plane wave can be focused into two focusing spots with the spacing of several wavelengths along the optical axis. The filter with the phase modulation functions are verified effective by numerical simulation. The distance of the two focuses and the position of each focus can be controlled and adjusted by changing the phase modulation functions. The beam quality and longitudinally polarization purity of these two focusing spots are calculated and discussed and thus the centrally obstructed four-quadrant phase filters are proposed to improve the beam quality.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
