title: Tailoring unidirectional angular radiation through multipolar interference in a single-element subwavelength all-dielectric stair-like nanoantenna.
abstract: The study of all-dielectric nanoantennas has become an emerging branch of the study of optical nanoantennas in recent years, with all-dielectric nanoantennas having an outstanding ability to tailor forward and backward unidirectional scattering arising from interference mainly between electric dipoles and magnetic dipoles induced simultaneously inside a nanoparticle. To further control their radiation properties, we demonstrate the off-normal scattering, by a silicon stair-like nanoantenna, of an incident near-infrared plane wave due to multipolar interference. The radiation angle could be tailored over a 20-degree range by tuning the geometric parameters of the nanoantenna. A multipolar model was adopted to interpret the interference among one electric dipole, two magnetic dipoles and one electric quadrupole induced inside the nanoantenna. The maximum radiation angle reached 20° at a wavelength near 1550 nm. Such a stair-like nanoantenna sets a good example for further flexible manipulation of multipolar resonances inside all-dielectric nanoparticles, which is an essential step towards practical application of all-dielectric nanoantennas in the near future.
authors.affiliation: State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, 310027, Hangzhou, China. qiangli@zju.edu.cn.
authors.forename: Jingyi
authors.initials: J
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, 310027, Hangzhou, China. qiangli@zju.edu.cn.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
authors.affiliation: State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, 310027, Hangzhou, China. qiangli@zju.edu.cn.
authors.forename: Yuanqing
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, 310027, Hangzhou, China. qiangli@zju.edu.cn.
authors.forename: Min
authors.initials: M
authors.lastname: Qiu