Upconversion luminescence of transparent Er3+-doped chalcohalide glass–ceramics

Upconversion luminescence of Er3+ ions in chalcohalide glass and in transparent glass–ceramic samples under continuous wave and pulsed laser excitation in the 4I9/2 level has been studied. Green and red emissions corresponding to (2H11/2, 4S3/2) → 4I15/2 and 4F9/2 → 4I15/2 transitions, respectively, have been observed and attributed to a two photon upconversion process. A significant increase of upconversion luminescence has been observed in the transparent glass–ceramics if compared with the one from the base glass. Moreover, the red emission corresponding to the 4F9/2 → 4I15/2 transition is enhanced in the glass–ceramics as compared to the green luminescence from (2H11/2, 4S3/2) levels probably due to an increase of the energy transfer processes populating the 4F9/2 level. The possible excitation mechanisms responsible for this upconversion luminescence are discussed.