Figure 3:

Schematic of various nanophotonic platforms for scintillation enhancement. (i) Plasmonic nanoparticles (study from Bignell et al.) provide localized field enhancement in small sub-wavelength mode volumes approximately the volume of the nanoparticle [55]. Such platforms with small mode volumes can result in scintillation enhancement provided many of them are distributed over large areas. (ii) High-Q metalenses are promising for focusing scintillated light while enhancing scintillation efficiency by coupling to high-Q resonances. (iii) Plasmonic SLRs provide higher field enhancements than isolated nanoparticles, with mode volumes that extend over the entire area of the array, while providing directional emission to the 0th diffraction order. (iv) 2D photonic crystals can boost emission intensity through field enhancements, as well as provide directional emission in the out-of-plane direction. These can be fabricated atop scintillating crystals, or by patterning the scintillating material itself (field enhancement value from Roques-Carmes et al.). (v) Unpatterned plasmonic films are able to provide moderate field enhancements while extending through large areas over the entire surface of conventional scintillators (field enhancement value from Ye et al.). (vi) 1D photonic crystals (field enhancement value from Kurman et al.) can provide enhancement in the emission intensity and directivity through low-Q resonances that extend through the entire volume of the photonic crystal. These can be made by alternating layers of scintillating materials with common dielectrics. With a sufficient number of layers, the enhancement volume can exceed mm³. For patterned structures, such as high-Q metalenses, plasmonic SLRs, and 2D photonic crystals, the mode volume will be dependent on the footprint of the nanophotonic structure.