Directly writing multicomponent plasmonic nanocavities based on fs-laser induced photo-mechanical spallation

Multicomponent plasmonic nanostructures exhibit enhanced resonant coupling and unique energy dissipation mechanisms, demonstrating out-standing application potential. However, the controllable fabrication of multicomponent plasmonic nanostructures in terms of composition, shape, and size, remains highly challenging. In this paper, we propose a method for controllable fabrication of multicomponent plasmonic nanocavity arrays through femtosecond laser directly writing. Based on the optically induced mechanical spallation effect, in-situ controllable direct writing of Au-Ag nanocavities was achieved and the size could be tuned within the range of 700 nm to 20 μm in diameter and 300 nm to 1.3 μm in height. The Au-Ag nanocavity structure showing a limit detection concentration of 10^-14 M of rhodamine (R6G) and an enhancement factor of 1.27 × 10⁸. Furthermore, the structure exhibited excellent physical and chemical stability, with a maxi-mum relative standard deviation of 3.02 % after exposure to air two months. In addition, other kinds of metal (Ag-Al) were also fabricated successfully, revealing highly universality of the fabrication method and making the method highly promising for widely applications.