Turning a hot spot into a cold spot: Fano-shaped local-field responses probed by a quantum dot

Optical nanoantennas can convert propagating light to local fields. Scientists in China demonstrate that in the nanogap of a nanoantenna, a local-field hot spot can be turned into a cold spot, and the spectral dispersion of the local-field response can exhibit dynamically tunable Fano lineshapes with nearly vanishing Fano dips. The results may inspire diverse designs of local-field responses with novel spatial distributions, spectral dispersions and temporal dynamics, and expand the available toolbox for nano-optics.