Guided-mode resonance assisted directional emission of a wavelength-shifting film for application in scintillation detection

Thin-film luminescent layers as wavelength shifters using in the scintillation detection system suffer with low efficiency due to the total internal reflection and the non-directional emission. In the present work, we design and fabricate a photonic crystal on the surface of LuTaO₄:Eu³⁺ thinfilm which is a newly developed luminescent material using in radiation detection systems. The entire structure shows guided-mode resonances with only one TE and TM mode. As a result, the emitting light is effectively extracted. Furthermore, due to only two modes existing in the layer, the directionality of emission is strongly controlled. This result enables the structured LuTaO₄:Eu³⁺ thin-film to be a potential wavelength shifter with high-efficiency.