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

ABSTRACT: Optical nanoantennas can convert propagating light to local fields. The local-field responses can be engineered to exhibit nontrivial features in spatial, spectral and temporal domains, where local-field interferences play a key role. Here, we design nearly fully controllable local-field interferences in the nanogap of a nanoantenna, and experimentally demonstrate that in the nanogap, the spectral dispersion of the local-field response can exhibit tuneable Fano lineshapes with nearly vanishing Fano dips. A single quantum dot is precisely positioned in the nanogap to probe the spectral dispersions of the local-field responses. By controlling the excitation polarization, the asymmetry parameter q of the probed Fano lineshapes can be tuned from negative to positive values, and correspo

SUBMITTER: Xia J 

PROVIDER: S-EPMC7505841 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature