Implementation of photonic crystal simulations into a Monte Carlo code to investigate light extraction from scintillators

Introduction: Nanostructures are used in various forms to increase light extraction from materials with a high refractive index [1,2]. Recently, photonic crystals (PhC) have been proposed to improve the light yield of scintillators used in high energy physics and medical imaging applications [3]. PhCs consisting of a thin slab with a periodically modulated refractive index serve to reduce total internal reflection at the scintillator extraction face. PhC coatings influence the reflection and transmission coefficients of photons impinging on the interface and the photon trajectory. A careful evaluation of the impact of PhCs on the total light yield and the propagation time distribution of extracted photons requires combined simulations in two regimes: i) interaction of electromagnetic waves with PhCs with dimensions similar to the wavelength which requires a full vectorial Maxwell solver and ii) propagation of photons inside the scintillator which is commonly derived from a Monte Carlo (MC) code using laws of geometric optics. This work examines the characteristics of PhCs using Rigorous Coupled Wave Analysis (GD-Calc, KJ Innovation) and ray-tracing (Radiant Zemax) for optical MC simulations.