Light can be confined to extreme dimensions by strongly coupling surface plasmons between two metallic nanostructures spaced a few nanometres apart. In this talk, I will show how light confinement is achieved down to 1nm^3 approaching quantum limits enabling strong coupling, Purcell-enhanced emission and optomechanics with single-bond vibrations. I will further show how the heat inevitably generated in molecular bonds directly pumped by a mid-infrared laser provides unique opportunities for single-photon detectors and sensing the dynamic topology of cell membranes with sub-nm resolution.

Plasmon resonances in metal nanoparticles generate nanoscale temperature gradients that can activate chemical reactions. In typical ensemble experiments, however, these local gradients vanish due to collective heating [1]. Here, we demonstrate how plasmonic photothermal effects generate nanoreactors by activating and spectroscopically following the growth of individual metal@semiconductor core@shell nanoparticles [2]. Plasmonic synthesis of functional nanomaterials otherwise inaccessible with classical colloidal methods opens applications in nanolithography, catalysis, energy conversion, and photonic devices.

[1] Baffou et al, Light Sci. Appl. 9, 108 (2020)

[2] Kamarudheen et al., Nature Comm. 11, 3957 (2020)

Large-area nanoscale patterning of optical interfaces represents a key issue for developing real-world applications of plasmonic antenna arrays with tunable response from the visible to the IR range. Our recent results demonstrate that ion beam wrinkling is a viable tool for inducing self-organised restructuring on a broad portfolio of optical interfaces which range from dielectrics to flexible polymers. The approach is scalable to the industrial level as a single step maskless process for the fabrication of hybrid plasmonic/dielectric arrays capable of high sensitivity SEIRA sensing, colour-routing and multifunctional electro-optic applications.