title: Highly-efficient continuous-wave intra-cavity frequency-doubled Yb:LuAG thin-disk laser with 1 kW of output power.
abstract: We report on the generation of continuous-wave, intra-cavity frequency-doubled, multi-mode laser radiation in an Yb:LuAG thin-disk laser. Output powers of up to 1 kW at a wavelength of 515 nm were achieved at an unprecedented optical efficiency of 51.6% with respect to the pumping power of the thin-disk laser. The wavelength stabilization and spectral narrowing as well as the polarization selection, which is necessary for a stable and efficient second-harmonic generation, was achieved by the integration of a diffraction grating into the dielectric end mirror of the cavity, which exhibits a diffraction efficiency of 99.8%. At a frequency-doubled output power of 820 W the peak-to-valley power fluctuations measured during 100 minutes of laser operation amounted to only 8.2 W (1.0%). The beam parameter product of the frequency-doubled output was 3.4 mm·mrad (M2≈ 20), which is suitable for standard beam delivery using fibers with a core diameter of 100 µm and a NA of 0.2.
authors.forename: Tom
authors.initials: T
authors.lastname: Dietrich
authors.forename: Stefan
authors.initials: S
authors.lastname: Piehler
authors.forename: Martin
authors.initials: M
authors.lastname: Rumpel
authors.forename: Philippe
authors.initials: P
authors.lastname: Villeval
authors.forename: Dominique
authors.initials: D
authors.lastname: Lupinski
authors.forename: Marwan
authors.initials: M
authors.lastname: Abdou-Ahmed
authors.forename: Thomas
authors.initials: T
authors.lastname: Graf