Quasi-three-level orthogonally polarized cw dual-wavelength operation in Nd:LiYF4

A diode-end-pumped quasi-three-level orthogonally polarized continuous-wave (cw) dual-wavelength Nd:LiYF4 (Nd:YLF) laser that generates simultaneous laser at the wavelengths 903 nm and 908 nm was demonstrated. Two types of cavity configurations were studied to support the stable dual-wavelength operation of the laser. A polarization beam splitter (PBS) was placed in the first type of cavity to split the beams polarizing in two orthogonal directions. At an absorbed pump power of 21.4 W, the cw output power obtained at 903 nm in π-polarization and 908 nm in σ-polarization is 0.43 W and 3.31 W, respectively. Furthermore, in order to balance the gain-to-loss, an uncoated glass plane was inserted in the second type of cavity. By adjusting the inclination of the glass plane relative to the optical axis of the resonator, we realized the stable simultaneous dual-wavelength operation. The cw output powers of 1.82 W at 903 nm and of 2.92 W at 908 nm were obtained.