Scanning probe microscope for Fermi’s Golden Rule
To realize this experimentally, the Resonant Nanophotonics group has built a scanning probe microscope (2011) in which emitters can be moved at will with nanometer resolution, to dynamically control light-matter interaction. We demonstrated reversible switching of the spontaneous emission rate of a single nano-source by a factor 2 in the near field of a plasmon nanowire, thereby showing that we can manipulate and image Fermi’s Golden Rule for spontaneous emission.
Frimmer Phys. Rev. Lett. 107, 123602 (2011)
Figure: We attach a fluorescent colloid to the end of a scanning probe tip. By scanning the tip over a photonic structure and measuring fluorescent lifetime we can spatially map the photonic local density of states in Fermi’s Golden Rule. The graph shows that fluorescent transitions accelerate by a factor 2 to 5 in close proximity to a metal nanowire, and recovers as soon as the source is moved away from the wire again.