title: Conical photonic crystals for enhancing light extraction efficiency from high refractive index materials.
abstract: We propose, analyze and optimize a two-dimensional conical photonic crystal geometry to enhance light extraction from a high refractive index material, such as an inorganic scintillator. The conical geometry suppresses Fresnel reflections at an optical interface due to adiabatic impedance matching from a gradient index effect. The periodic array of cone structures with a pitch larger than the wavelength of light diffracts light into higher-order modes with different propagating angles, enabling certain photons to overcome total internal reflection (TIR). The numerical simulation shows simultaneous light yield gains relative to a flat surface both below and above the critical angle and how key parameters affect the light extraction efficiency. Our optimized design provides a 46% gain in light yield when the conical photonic crystals are coated on an LSO (cerium-doped lutetium oxyorthosilicate) scintillator.
authors.forename: Jeong-Gil
authors.initials: JG
authors.lastname: Kim
authors.forename: Chih-Hung
authors.initials: CH
authors.lastname: Hsieh
authors.forename: Hyungryul J
authors.initials: HJ
authors.lastname: Choi
authors.forename: Jules
authors.initials: J
authors.lastname: Gardener
authors.forename: Bipin
authors.initials: B
authors.lastname: Singh
authors.forename: Arno
authors.initials: A
authors.lastname: Knapitsch
authors.forename: Paul
authors.initials: P
authors.lastname: Lecoq
authors.forename: George
authors.initials: G
authors.lastname: Barbastathis