title: Highly efficient 400  W near-fundamental-mode green thin-disk laser.
abstract: We report on the efficient generation of continuous-wave, high-brightness green laser radiation. Green lasers are particularly interesting for reliable and reproducible deep-penetration welding of copper or for pumping Ti:Sa oscillators. By intracavity second-harmonic generation in a thin-disk laser resonator designed for fundamental-mode operation, an output power of up to 403 W is demonstrated at a wavelength of 515 nm with almost diffraction-limited beam quality. The unprecedented optical efficiency of 40.7% of green output power with respect to the pump power of the thin-disk laser is enabled by the intracavity use of a highly efficient grating waveguide mirror, which combines the functions of wavelength stabilization and spectral narrowing, as well as polarization selection in a single element.
authors.forename: Stefan
authors.initials: S
authors.lastname: Piehler
authors.forename: Tom
authors.initials: T
authors.lastname: Dietrich
authors.forename: Martin
authors.initials: M
authors.lastname: Rumpel
authors.forename: Thomas
authors.initials: T
authors.lastname: Graf
authors.forename: Marwan Abdou
authors.initials: MA
authors.lastname: Ahmed