Power scaling of fundamental-mode thin disk laser using gain enhanced soft aperture resonator

We present a novel, compact resonator design for large-mode thin-disk lasers, producing 300 W average output power at a 1-kHz repetition rate within a cavity length of less than 5 m.High beam quality with M 2 x=1.06 and M 2 y=1.15 is achieved by breaking conventional mode-matching ratios and fully exploiting the disk 's soft-aperture effect.In this work, a Yb:YAG thin-disk resonator is shown to produce fundamental transverse mode lasing with a mode size approaching or surpassing the pump spot dimension.Theoretical analysis demonstrates that the proposed cavity configuration enables a thindisk regenerative amplifier to deliver pulse energy exceeding 200 mJ at 1 kHz repetition rate with excellent beam quality.