title: Femtosecond Kerr-lens mode locking with negative nonlinear phase shifts.
abstract: We report a Kerr-lens mode-locked Cr:forsterite laser operated with negative nonlinear phase shift. The nonlinear phase shift is induced by the cascade chi((2;)):chi((2)) process in a lithium triborate crystal. Employing the cascade process at large phase mismatch produces a nearly linear frequency chirp. Transform-limited pulses as short as 60 fs are generated with positive cavity dispersion.
authors: L J
authors: LJ
authors: Qian
authors: X
authors: X
authors: Liu
authors: F W
authors: FW
authors: Wise