LAUSR

Abstract Scintillators are widely used in ionization radiation detection. The light extraction efficiency and thus the effective light output of scintillators are limited by the total internal reflection due to their high refractive indices. Furthermore, scintillators have an approximate Lambertian profile for the spatial distribution of the light emission, which is detrimental to the collection of light. In this paper, hollow microlens arrays (HMLAs) composed of periodic arrangement of individual hollow shell hemispherical microlenses are proposed to achieve the directional light extraction enhancement of scintillators. The optical properties of HMLAs can be conveniently adjusted by varying the refractive index and the thickness of the shell layer. Simulation results reveal that the refractive index and the thickness of the shell of the individual hollow microlenses are the key parameters to achieve the control of the light output of scintillators. The measurement results of the prepared HMLAs-coated LYSO scintillator are consistent with the prediction of the numerical simulations. This scheme of directional light extraction enhancement by HMLAs is also applicable to other light-emitting devices that have the requirement of directional emission.