Japanese Journal of Applied Physics
Femtosecond Free Induction Decay Beats in Nd3+:YAG Crystal
Ryuzi Yano, Naoshi Uesugi
Abstract
Femtosecond free induction decay (FID) beats were observed for the 4F3/2 - 4I9/2 transition of Nd3+ ions doped in Y3Al5O12 (YAG) crystal at room temperature using a mode-locked Ti3+:Al2O3 laser. This is the first observation of room-temperature dephasing processes in the time domain for rare-earth ion doped materials. The FID beat signal shows a dip structure produced by the interference between the pump pulse and the FID signal, and a quantum beat. The FID signal became large and comparable to the pump pulse as the crystal length was increased. The FID intensity evolution due to the pulse propagation is explained well by phenomenological equations.