We propose an approach for generating the enhanced superchiral needle by matching electromagnetic components of the combined field,which is the superposition of a radially polarized vortex Bessel–Gaussian beam(RPVBGB...We propose an approach for generating the enhanced superchiral needle by matching electromagnetic components of the combined field,which is the superposition of a radially polarized vortex Bessel–Gaussian beam(RPVBGB)and an azimuthally polarized Bessel–Gaussian beam(APBGB).In the tightly focused combined field,the longitudinal magnetic component provided by the APBGB,together with the longitudinal electric component provided by the RPVBGB,induces an additional contribution to the optical chirality and thereby significantly improves the enhancement factor of the superchiral needle.It is revealed that the characteristics of the superchiral needle are mainly influenced by the ring aperture,the phase difference,and the amplitude ratio.Under proper parameters,the enhancement factor can reach from 22.9 to 32.9,and the needle width can reach from 0.0151λto0.0043λand from 0.0182λto 0.0058λin the x-and y-directions,respectively.The results would be of interest for the chirality measurement of individual molecules.展开更多
基金Guangdong Basic and Applied Basic Research Foundation(2023A1515012432,2025A1515012099)。
文摘We propose an approach for generating the enhanced superchiral needle by matching electromagnetic components of the combined field,which is the superposition of a radially polarized vortex Bessel–Gaussian beam(RPVBGB)and an azimuthally polarized Bessel–Gaussian beam(APBGB).In the tightly focused combined field,the longitudinal magnetic component provided by the APBGB,together with the longitudinal electric component provided by the RPVBGB,induces an additional contribution to the optical chirality and thereby significantly improves the enhancement factor of the superchiral needle.It is revealed that the characteristics of the superchiral needle are mainly influenced by the ring aperture,the phase difference,and the amplitude ratio.Under proper parameters,the enhancement factor can reach from 22.9 to 32.9,and the needle width can reach from 0.0151λto0.0043λand from 0.0182λto 0.0058λin the x-and y-directions,respectively.The results would be of interest for the chirality measurement of individual molecules.
