Dual-central-wavelength passively mode-locked diffusion-bonded Nd:YVO4/Nd:GdVO4 laser with a semiconductor saturable absorber mirror

Abstract

A dual-central-wavelength passively mode-locked laser with full modulation in the 0.31 THz optical beating is achieved by using a diffusion-bonded Nd:YVO4/Nd:GdVO4 crystal and a semiconductor saturable absorber mirror. The output power of the dual-band emission is well balanced by tuning the focal position of the pump waist. At a pump power of 13 W, the total output power is up to 2.7 W with a repetition rate of 297.9 MHz. The autocorrelation traces clearly reveal the synchronization of the dual-band emission. Moreover, an analytical model is developed to manifest the multi-pulse structure caused by the etalon effect of the gain medium. More important, we experimentally verify that the etalon effect can be completely eliminated by using the wedge-cut diffusion-bonded Nd:YVO4/Nd:GdVO4 crystal.