Scanning nanogap cavity microscopy

• Applicant: Professor Dr. Friedemann Reinhard
• Subject Area: Experimental Condensed Matter Physics ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 565033315

Can we build a microscope that can see objects with nanometer-scale resolution, 10.000 times brighter than they would appear to the naked eye? What would we look at if we had such an instrument? In the past decade plasmonics has given an affirmative answer to the first question. Arrangements of metallic nanoparticles can confine light onto atomic scales, providing simultaneously nanoscale resolution and ultrastrong light-matter coupling. However, these spectacular achievements have largely remained limited to carefully assembled stationary nanostructures. Turning this power into an imaging technique, and answering the second question, is the mission of the present project. The project will develop a scanning nanogap cavity microscope (SNCM). In this device, a plasmonic nanoparticle, attached to a planar glass platform, is scanned at a controlled fly height of few nanometers across a metallic mirror, forming a plasmonic nanogap cavity. Samples are imaged by raster scanning through the cavity mode, collecting fluorescence or scattered light from the top. Scanning is enabled by planar scanning probe microscopy, a technique pioneered among others by my laboratory. We will develop this instrument and explore two first areas of application: the study of nanogap cavities under in situ tuning, as well as imaging and study of luminescent defect centers.

• DFG Programme: Research Grants