Pump and probe measurements of optical amplification at 584 nm in dysprosium doped lithium niobate crystal

Usually the Dy3+ ions have been used as laser sources associated with the 6H13/2 → 6H15/2 transition about 3 μm. However, these ions exhibit emissions in the blue (480 nm) and in the yellow (575 nm) that are promising for laser operations. In this work, positive optical gain about 1.9 cm−1 (∼8.2 dB/cm) has been observed at 584 nm in trivalent dysprosium doped lithium niobate crystal, Dy:LiNbO3, using a pump and probe experimental setup. High power laser pulses at 475 nm have been used as the pump source in order to strongly populate the 4F9/2 level of the Dy3+ ions due to ground state absorption. Low signal beam cw radiation at 584 nm has been used as the probe beam to stimulate the emission associated with the 4F9/2 → 6H13/2 electronic transition of the Dy3+ ions. The process has been modelled as a four level system and the level populations have been analysed and simulated in order to study the gain dynamics. Optical amplification of the probe signal has been observed during the first 300 μs, which represents a good agreement between the measured lifetime of the 4F9/2 level and the proposed simulation.