Function of Eu ion and defect centers in photochemical hole-burning of Eu-doped sodium borate glass

Abstract

Photochemical hole-burning of Eu-doped sodium borate glass is investigated as a function of doped ion concentration (0.1 and 0.3 mol%) and X-ray irradiation time (5, 10 min and longer) upon preparation. When the concentration is low, photochemical hole is formed only after X-ray irradiation. However, its stability against temperature is low. Therefore, contrary to reports in the literature, both defect centers created by X-ray and Eu2+ ion adjacent to a Eu3+ ion excited site selectively are responsible for the formation of photochemical hole with high temperature durability.