The massless photons can be effective energy and information carriers like electrons in the solid. However, compared with the electronic devices with sizes down to a few nanometers, the current photonic devices are limited to scales of a few hundred nanometers due to the apparent much longer wavelength of matter waves of photons.

    We strive to circumvent this limitation by shrinking the light to the nanoscale and exploring the light-matter interactions in the deep-sub-wavelength regions. The plasmonics of metallic nanoparticles provides the means to confining and shaping the optical fields beyond the diffraction limit, even down to atomic scales. Our current interests are focused on the following aspects:

    1. Studying the interaction between light and a single emitter or molecule at the nanoscale and developing methods to probe, control, and manipulate these single emitters or molecules.

    2. Exploring the strong light-matter coupling regime, where the light and matter are hybridized together and form polaritons. Our goal is to utilize these "half-light, half-matter" polaritons to tailor the intrinsic physical or chemical properties of the coupled materials.

Fig.1 The schematics of optical field confined by a plasmonic cavity, which consist of a silver nanocube and metallic mirror. The right panel show a scanning electron microscope image of such cavity.