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. The local-field responses can be engineered to exhibit nontrivial features in spatial, spectral and temporal domains. Local-field interferences play a key role in the engineering of local-field responses. By controlling local-field interferences, researchers have demonstrated local-field responses with various spatial distributions, spectral dispersions and temporal dynamics. Different degrees of freedom of the excitation light have been used to control local-field interferences, such as polarization, beam shape and beam position, and incidence direction. Despite remarkable progress, achieving fully controllable local-field interferences remains a major challenge. A fully controllable local-field interference should be controllable between a constructive interference and a complete destructive interference. This would bring unprecedented benefit for the engineering of local-field responses.