Research

Atomic-scale nanophotonics

How are the rules of light⁠–⁠matter interaction rewritten when the field varies across a single emitter?

By atomic scale we mean critical dimensions of one to ten nanometers: the size of a molecule, and of the gaps in our cavities. We design and fabricate optical cavities with gaps of a few nanometers, where light is confined to volumes more than ten thousand times smaller than a cubic wavelength. In this regime the usual rules of light⁠–⁠matter interaction stop applying: field gradients can couple to transitions that are dipole-forbidden, the vacuum becomes strongly anisotropic, and the cavity’s own structure — down to the last nanometer — becomes a design variable.

We map these new rules experimentally across hundreds of cavities at a time rather than one device at a time, and use them to create light⁠–⁠matter interactions that have no counterpart in free space.

Key papers

• Probing the mechanisms of large Purcell enhancement in plasmonic nanoantennas
  G. M. Akselrod, C. Argyropoulos, T. B. Hoang, C. Ciraci, C. Fang, J. Huang, D. R. Smith, M. H. Mikkelsen, Nature Photonics 8, 835⁠–⁠840 (2014) · DOI
• Extreme nanophotonics from ultrathin metallic gaps
  J. J. Baumberg, J. Aizpurua, M. H. Mikkelsen, D. R. Smith, Nature Materials 18, 668⁠–⁠678 (2019) · DOI — review
• Control of radiative processes using tunable plasmonic nanopatch antennas
  A. Rose, T. B. Hoang, F. McGuire, J. J. Mock, C. Ciraci, D. R. Smith, M. H. Mikkelsen, Nano Letters 14, 4797⁠–⁠4802 (2014) · DOI
• Large-area metasurface perfect absorbers from visible to near-infrared
  G. M. Akselrod, J. Huang, T. B. Hoang, P. T. Bowen, L. Su, D. R. Smith, M. H. Mikkelsen, Advanced Materials 27, 8028⁠–⁠8034 (2015) · DOI — front cover article