Temporal evolution of a coherent stimulated radiation pulse in the three-level system in a Pr3+ : LaF3 crystal

The temporal characteristics of coherent stimulated radiation at the ³P₀– ³H₆ transition in the Pr³⁺ ion in a LaF₃ matrix are studied by tuning the pump frequency in the vicinity of the ³H₄– ³P₀ transition. It is found that in the case of the exact tuning to the resonance, a laser pulse, consisting of a train of picosecond spikes of total duration about 10 ns, was delayed by 3–4 ns with respect to the pump pulse onset. As the pump pulse detuning was increased, the shape of the coherent laser pulse changes and its delay increased up to 10 ns. The experimental results are interpreted theoretically.