Flexibly Controlling the Power Ratio of Dual-Wavelength SESAM-Based Mode-Locked Lasers With Wedged-Bonded Nd:YVO4/Nd:GdVO4 Crystals

A new diffusion-bonded Nd:YVO
₄
/Nd:GdVO
₄
hetero-structure crystal with oblique interface between two vanadate materials is exploited to achieve dual-wavelength passively mode-locked laser with a semiconductor saturable absorber mirror. Experimental results show that the power ratio of the two emission wavelengths can be flexibly adjusted by controlling the vertical position of pump beam. In the optimally balanced dual-wavelength operation, the maximum total output power of 2.5 W is obtained at an incident pump power of 11 W and the pulse width is measured to be 24.7 ps with pulse repetition rate of 296.6 MHz. The mode-locked output pulse is further found to exhibit an optically beating with pulse duration of 1.8 ps at a repetition rate of 0.318 THz.