High-Q Plasmonic Resonance Modes for Purcell Enhanced Scintillation

We performed finite-difference time-domain electromagnetic simulations of a hybrid plasmonic-photonic crystal for Purcell enhanced scintillation. The Purcell effect can be explained by cavity quantum electrodynamics and can be calculated from Maxwell's equations. Fermi's Golden Rule states that the radiative rate of a quantum emitter is proportional to the local density of optical states of a medium. We have designed a nanocomposite structure that is a Purcell enhanced "superscintillator" and can be fabricated by interspersing metallic nanoparticles with scintillating cube-shaped nanoparticles that we have previously developed and synthesized. The resulting nanocomposite structure creates an optimal spatial overlap between the optical resonance modes and localized surface plasmon resonance (LSPR) of the metallic nanoparticles. From simulations assuming aluminum plasmonic nanoparticles in unit cells that are 150 nanometers thick, we demonstrate a peak Purcell factor of over 300 at the peak emission frequency (350 nm) of our cerium-doped SrLuF nanoparticles. This much higher resulting radiative decay rate of this metamaterial scintillator design enables 300-fold higher light yield and shorter decay times, which if successfully scaled up in dimensions, would be a promising advance for the next generation time-of-flight positron emission tomography detectors.