Enhancement of photoluminescence of glass phosphor by nanoimprint of moth-eye structure

Abstract

We demonstrated that a moth-eye surface pattern on the luminous inorganic glass could enhance the photoluminescence (PL) intensity notably. A moth-eye pattern of a square array of cones at pitch of 250 nm was fabricated on Eu³⁺-doped MgF₂–MgO–BaO–B₂O₃ glass by thermal nanoimprinting at 520°C. A simulation with rigorous coupled-wave analysis demonstrated that the surface structure could reduce the surface reflectance in the optical input for the excitation wavelength λ of 405 nm, i.e., −1.1% for p-polarized light, 10.6% for s-polarized light, and 4.1% for non-polarized light in total of a half round angle for the irradiation from a surface light source. The angularly dependent PL of the excitation angle on the nanoimprinted glass was measured by an excitation of UV laser diode (λ = 405 nm). The enhancements of ∼0% for p-polarized light and ∼9% for s-polarized light were observed at the incident angle = 5°.