A new record for cw thin-disk-lasers emitting in the green spectral range has been established at the IFSW within the EU funded project “TiSa-TD”. At a wavelength of 515 nm more than 400W of output power were achieved by intra-cavity second-harmonic-generation with an unprecedented overall optical efficiency of approximately 40% and an almost diffraction-limited beam quality. Potential applications for such a laser range from material processing of materials such as e.g. copper to the use as a pump source for Titan:Sapphire lasers.
The high efficiency and the good beam quality was achieved by the use of a grating-waveguide structure on the resonator’s end-mirror. For stable and efficient frequency conversion, the laser radiation circulating inside the resonator has to feature a well-defined state of linear polarization and a narrow spectral bandwidth. Furthermore, the central wavelength of the laser radiation has to be stabilized in order to avoid a spectral shifting. With the use of the grating-waveguide mirror, these functionalities were combined in one single, highly efficient optical element, which eliminates the necessity of further potentially lossy optical components inside the laser resonator.
Further information is given in S. Piehler, T. Dietrich, M. Rumpel, T. Graf and M. Abdou Ahmed: „Highly efficient 400W near-fundamental-mode green thin-disk laser“ in Optics Letters 41 (1), 171 (2016).
Contact: Dr. Marwan Abdou Ahmed