Physics in Nanogaps

Extreme trapping in nanoparticle-on-mirror

We have pushed the development of nanocavities which confine light to <1nm high and 5nm wide. They are easy to make, robust, scalable, and offer superb opportunities for novel light-matter interactions. These ‘NPoM’ systems have strong resonances that can be tuned by gap spacing and nanoparticle diameter across the visible and infrared. [1]

Precision nano-decahedra-on-mirror

By using nanoparticles which have the identical triangular facets on each side (decahedra), we can make robust nanocavities with reduced spectral variation. We explore how the symmetry breaking changes emission, absorption, and vibrational spectroscopies. [2]

Facet control of nanocavity fields

We have developed ways to model the influence of the shape of the lower facet of the nanoparticle on the spectral resonances, and the shapes of each optical mode inside the nanocavity. This is crucial to understand the spectra observed in experiments. [3]

Lasing in extreme nanocavities

When emitters are placed inside the plasmonic nanocavities, their light-matter coupling is vastly enhanced. This allows us to create lasers with only a single emitter, but they have unusual properties unlike any conventional laser. [4]

Collective vibrations inside nanocavities

Typically we place single layers of molecules inside the NPoM cavities. However when we excite vibrations on a single molecule, this can couple to all the nearby molecules, creating a mixed excitation which is more stable as it is delocalised. [5]

Strong coupling with single emitters

Because the nanocavity confines light so tightly, even a single emitter can couple to the confined plasmon so tightly so that the energy flips back and forth between them faster than it escapes. This creates new mixed ‘polaritons’ (here ‘plexcitons’) with different properties, such as new chemistry. [6]