Modified spontaneous emission in nanophotonic structures

Spontaneous emission is not an inherent property of a luminescent material; rather, it arises due to interaction between the material and its local electromagnetic environment. Changing the environment can thus alter the emission rate, with potential applications in sensing, integrated photonics and solar energy conversion. Significant increases in emission rate require an optical resonator that stores light in as small a volume as possible, for as long as possible. This is currently achieved using two main systems: photonic crystal microcavities and plasmonic metal nanoparticles. These two systems have largely been developed independently, but the underlying physical mechanisms are the same. Comparing the two provides insight into emission modification and illustrates some of the subtleties involved in interpreting experimental results.