Re-absorption process in the upconversion green emission of the erbium ion-doped fluorozirconate glass system

Abstract In this paper we report the upconversion emission for the 4 S 3/2 → 4 I 15/2 Stark components of Er 3+ ion-doped fluorozirconate glass at T =2 K. The spectrum shows only seven peaks, one less than expected theoretically, being missing the peak at the wave number 17,996 cm −1 ( λ =555 nm). This result is compared with the luminescence for the same transition at the same conditions which exhibits the eight expected lines. Such a discrepancy is attributed to a re-absorption process (ESRA) between the energy levels 4 I 13/2 and 2 H 9/2 .