Soliton-Modelocked 153-W Thin-Disk Laser Oscillator in Air Enabled by Negative Nonlinearities in a Phase-Mismatched χ(2) Crystal

We use a phase-mismatched χ(2) crystal to cancel the nonlinearities caused by intracavity air. We obtain 153 W average output power in an air-filled cavity, which is a record value for non-vacuum/non-helium SESAM modelocked lasers.