Plasmonic Coupling in Silver Nanocomposite Glasses

This work demonstrates that an enhanced plasmonic response can be attained and tuned for Ag nanocomposite glasses via a real-time in situ control of the plasmonic coupling between closely spaced Ag nanoparticles (NPs). The result is achieved by a two-step modification of Ag NP-doped glasses. First, confined “super-nucleation” domains are induced by high-fluence nanosecond laser irradiation promoting photofragmentation of Ag NPs in the matrix. Photoluminescence and Raman scattering spectroscopies are put to use in assessing the effects of laser treatment. Subsequently, a particle regrowth process leading to the development of strongly interacting NPs is activated during an in situ isothermal processing, which also allows for the tuning of the optical response of the material in real time. An important finding is that the post-laser thermal treatment results in a significant narrowing of the Ag NP size distribution as revealed by transmission electron microscopy. Further, valuable insights on the laser-induced “super-nucleation” and NP regrowth process leading to plasmonic coupling are obtained through a quantitative assessment employing the theoretical model for NP aggregates from Quinten and Kreibig, together with the Kolmogorov–Johnson–Mehl–Avrami (KJMA) theory of phase transformations. The activation energy of the post-laser NP regrowth process was estimated at 0.8(±0.1) eV, based on the solid-state precipitation kinetics. The current report is expected to open new avenues of research on plasmon-enhanced processes inside dielectrics with relevance to both fundamental and applied nanoscience.