Optoplasmonic tuneable response by femtosecond laser irradiation of glass with deep-implanted gold nanoparticles

The manipulation of the optical properties of plasmonic nanocomposites is of high interest for the development of advanced optical devices with tailored unique properties. Achieving these objectives requires a combination of synthesis techniques and post-fabrication strategies. Here, we combine the use of two well-established physical strategies: MeV ion implantation and femtosecond laser processing. Firstly, we synthesize Au-doped soda lime glass nanocomposite through ion beam implantation (Au²⁺ at 1.8 MeV) followed by thermal annealing. This synthesis procedure results in a peculiar optical response based on the combination of Au-nanoparticle plasmonic resonance and a Fabry-Perot interference, caused by the deep implantation (centered at 480 nm). Secondly, this dual response is demonstrated to be highly tuneable by non-resonant femtosecond laser irradiation (800-nm wavelength and 130-fs pulse duration). Depending on the laser fluence, three transformation regimes are distinguished: supressing the interferometric response by spallative ablation, inducing vivid blue colors by surface swelling, and producing red-shifted color changes by multi-shot irradiation at low fluences. The proposed method is very versatile, since it is applicable to any dielectric matrix or implanted element. This work paves the way to a new route for the development of scalable and tuneable nanocomposites with several potential applications in optics.