Stark splitting of the ground state of Er3+ in fluorozirconate glass at low temperature

Optical properties of Er3+-doped ZBLAN glass matrix have been studied by luminescence spectroscopy under 488 nm excitation. The spectrum of the 4S3/2 4I15/2 transition, carried out at temperature T = 2 K, shows a new line in the lowest energy region. This new line, centered at 17 996 cm−1, was attributed to the lower transition between the Stark components of the 4S3/2 4I15/2 transition. Measurements from T = 2 K to room temperature show the disappearance of this new line. From the results we estimate the splitting of 415 cm−1 for the ground state and 100 cm−1 for the 4S3/2 excited multiplet. The experimental result allows us to assign the positions of the eight Stark components of the ground state multiplet of the Er3+ in the ZBLAN glass matrix.