The theoretical and experimental results of tightly focused radially polarized vortex beams are demonstrated. An auto-focus technology is introduced into the measurement system in order to enhance the measurement prec...The theoretical and experimental results of tightly focused radially polarized vortex beams are demonstrated. An auto-focus technology is introduced into the measurement system in order to enhance the measurement precision, and the radially polarized vortex beams are generated by a liquid-crystal polarization converter and a vortex phase plate. The focused fields of radially polarized vortex beams with different topological charges at numerical apertures （NAs） of 0.65 and 0.85 are measured respectively, and the results indicate that the total intensity distribution at focus is dependent not only on the NA of the focusing objective lens and polarization pattern of the beam but also on the topological charge l of the beam. Some unique focusing properties of radially polarized vortex beams with fractional topological charges are presented based on numerical calculations. The experimental verification paves the way for some practical applications of radially polarized vortex beams, such as in optical trapping, near-field microscopy, and material processing.展开更多
Broadband transverse displacement sensing by exploiting the interaction of a focused radially polarized beam with a silicon hollow nanodisk is proposed.The multipolar decomposition analysis indicates that the interfer...Broadband transverse displacement sensing by exploiting the interaction of a focused radially polarized beam with a silicon hollow nanodisk is proposed.The multipolar decomposition analysis indicates that the interference between a longitudinal total electric dipole(TED)moment and a lateral magnetic dipole(MD)moment is dominant in the far-field transverse scattering in the near-infrared region.Within a broadband wavelength range with the width of 155 nm,the longitudinal TED is almost in phase with the lateral MD,and then broadband position sensing based on the sensitivity of scattering directivity to transverse displacement can be achieved.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 61108047 and 60908015)the Beijing Excellent Talent Training Project,China (Grant No. 2011D005007000008)
文摘The theoretical and experimental results of tightly focused radially polarized vortex beams are demonstrated. An auto-focus technology is introduced into the measurement system in order to enhance the measurement precision, and the radially polarized vortex beams are generated by a liquid-crystal polarization converter and a vortex phase plate. The focused fields of radially polarized vortex beams with different topological charges at numerical apertures （NAs） of 0.65 and 0.85 are measured respectively, and the results indicate that the total intensity distribution at focus is dependent not only on the NA of the focusing objective lens and polarization pattern of the beam but also on the topological charge l of the beam. Some unique focusing properties of radially polarized vortex beams with fractional topological charges are presented based on numerical calculations. The experimental verification paves the way for some practical applications of radially polarized vortex beams, such as in optical trapping, near-field microscopy, and material processing.
基金This work was supported by the Key Program of the Natural Science Foundation of Tianjin(No.19JCZDJC32700)the Science and Technology Support Program of Tianjin(No.17YFZCSY00740)。
文摘Broadband transverse displacement sensing by exploiting the interaction of a focused radially polarized beam with a silicon hollow nanodisk is proposed.The multipolar decomposition analysis indicates that the interference between a longitudinal total electric dipole(TED)moment and a lateral magnetic dipole(MD)moment is dominant in the far-field transverse scattering in the near-infrared region.Within a broadband wavelength range with the width of 155 nm,the longitudinal TED is almost in phase with the lateral MD,and then broadband position sensing based on the sensitivity of scattering directivity to transverse displacement can be achieved.
