Reflective Meta-Films with Anti-Damage Property via Field Distribution Manipulation

Coatings

Zao Yi¹  Jun Chen²  Feng Tang²  Xin Ye²  Yiqun Wang³  Haichao Yu³ 

[1] Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology, Mianyang 621010, China;Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China;Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215125, China;

关键词: metasurfaces;    reflective films;    field confinement;    intense-light systems;   

DOI  :  10.3390/coatings11060640

来源: DOAJ

【 摘 要 】

The reflective optical multi-films with high damage thresholds are widely used in intense-light systems. Metasurfaces, which can manipulate light peculiarly, give a new approach to achieve highly reflective films by a single-layer configuration. In this study, reflective metasurfaces, composed of silicon nanoholes, are numerically investigated to achieve high damage thresholds. These nanoholes can confine the strongest electric field into the air zone, and, subsequently, the in-air electric field does not interact directly with silicon, attenuating the optothermal effect that causes damage. Firstly, the geometrical dependencies of silicon nanoholes’ reflectance and field distribution are investigated. Then, the excitation states of electric/magnetic dipoles in nanostructures are analyzed to explain the electromagnetic mechanism. Furthermore, the reflection dependences of the nanostructures on wavelength and incident angle are investigated. Finally, for a typical reflective meta-film, some optothermal simulations are conducted, in which a maximum laser density of 0.27 W/µm² can be handled. The study provides an approach to improve the laser damage threshold of reflective nanofilms, which can be exploited in many intense-light applications.

【 授权许可】

Unknown