  Bombardment of materials by high-energy particles (e.g., electrons, nuclei,
X- and $\gamma$-ray photons) often leads to light emission, known generally as
scintillation. Scintillation is ubiquitous and enjoys widespread applications
in many areas such as medical imaging, X-ray non-destructive inspection, night
vision, electron microscopy, and high-energy particle detectors. A large body
of research focuses on finding new materials optimized for brighter, faster,
and more controlled scintillation. Here, we develop a fundamentally different
approach based on integrating nanophotonic structures into scintillators to
enhance their emission. To start, we develop a unified and ab initio theory of
nanophotonic scintillators that accounts for the key aspects of scintillation:
the energy loss by high-energy particles, as well as the light emission by
non-equilibrium electrons in arbitrary nanostructured optical systems. This
theoretical framework allows us, for the first time, to experimentally
demonstrate nearly an order-of-magnitude enhancement of scintillation, in both
electron-induced, and X-ray-induced scintillation. Our theory also allows the
discovery of structures that could eventually achieve several
orders-of-magnitude scintillation enhancement. The framework and results shown
here should enable the development of a new class of brighter, faster, and
higher-resolution scintillators with tailored and optimized performances - with
many potential applications where scintillators are used.
