Orthogonally polarized dual-wavelength Nd:LiYF4 laser at 1777 and 1789 nm with 1:1 output power ratio

A diode-pumped continuous-wave orthogonally polarized dual-wavelength Nd:LiYF4 (Nd:YLF) laser on( 4 )F (3/2) -> (4) I (15/2) transition is studied. The output power ratio can be adjusted using two intracavity uncoated glass plates. At an incident pump power of 20 W, a dual-wavelength laser operating at 1777 nm in pi-polarization and 1789 nm in sigma-polarization was realized. The total output power of the dual-wavelength laser was more than 1.16 W with a 1:1 output power ratio. The total slope efficiency and total optical conversion efficiency with respect to the incident pump power were 4.6% and 2.9%, respectively. To the best of our knowledge, this is the first work realizing mid-infrared wavelength operation in Nd:YLF lasers on F-4 (3/2) -> (4) I (15/2) transition.