Focusing light with a metal film coated patchy particle

Posted on 2023-03-10 - 14:18
Microsphere-assisted super-resolution imaging is a promising technique that can significantly enhance the resolution of conventional optical microscopes. The focus of a classical microsphere is called photonic nanojet, which is a symmetric high-intensity electromagnetic field. Recently, patchy microspheres have been reported to have superior imaging performance than pristine microspheres, and coating microspheres with metal films leads to the formation of PHs, which can enhance the imaging contrast of microspheres. Understanding the influence of metal patches on the near-field focusing of patchy particles is important for the rational design of a nanostructured microlens. In this work, we theoretically and experimentally showed that the light waves can be focused and engineered using patchy particles. When coating dielectric particles with Ag films, light beams with a hook-like structure or S-shaped structure can be generated. Simulation results show that the waveguide ability of metal films and the geometric asymmetry of patchy particles cause the formation of S-shaped light beams. Compared with classical PHs, S-shaped photonic hooks have a longer effective length and a smaller beam waist at far-field region. Experiments were also carried out to demonstrate the generation of classical and S-shaped photonic hooks from patchy microspheres.


Xu, Chu; Ye, Ran; Zou, Pengxin; Yang, Tianyu; Melinte, Sorin; Wang, Zengbo; et al. (2023): Focusing light with a metal film coated patchy particle. Optica Publishing Group. Collection.
Select your citation style and then place your mouse over the citation text to select it.



Usage metrics

Optics Express


Chu Xu
Ran Ye
Pengxin Zou
Tianyu Yang
Sorin Melinte
Zengbo Wang
Chao Zuo
need help?