Comparison between Two Kinds of Semiconductor Absorbers for Mode-Locking in Nd:YVO₄ Laser

We have demonstrated passive mode-locking in a diode-end-pumped Nd:YVO₄ laser using two kinds of semiconductor absorbers whose relaxation region comes from In_0.25Ga_0.75As grown at low temperature (LT) and GaAs/air interface respectively. Mode-locking, using absorbers of the GaAs/air interface relaxation region, has the characteristics of less Q-switching tendency and higher average output power than that using absorbers of LT In_0.25Ga_0.75As relaxation region, but is not as stable as the latter.