Metallodielectric optical antenna for ultrastrong enhancement of spontaneous emission

31.10.2012, 14:42

Newsletter 5

Modification of spontaneous emission has been a topic of theoretical and experimental research over the past four decades. Early efforts considered flat interfaces, Fabry-Perot resonators, photonic crystals and other structured dielectric materials. Recent reports have shown that metallic nanoparticles can enhance emission in analogy with antenna concepts from radio engineering. However, due to the dissipation in the metal, it is difficult to achieve ultrastrong enhancement of the emission without invoking quenching. Here we combine metallic antennas with planar dielectric structures and exploit design strategies from antennas and concepts from cavity QED to maximize the emission and minimize the losses. One realization of the metallodielectric antenna consists of a gold nanocone placed in contact with a high-index substrate where a single emitter is embedded right beneath the nanocone. As shown in the figure, we obtained nearly four orders of magnitude enhancement of the spontaneous emission while keeping a very large quantum efficiency. With such a simple arrangement, we bring about the prospect of triggered single-photon sources to the ?W power level and also open the door to a paradigm where the radiative processes become comparable with or faster than many vibrational and phononic interactions, leading to unexplored regimes of photophysical dynamics.

 

Contact: xuewen.chen(at)mpl.mpg(dot)de
Group:
Sandoghdar Division
Reference: X. Chen et al., Phys. Rev. Lett.
108233001 (2012).