Compact fiber-delivered Cr:forsterite laser for nonlinear light microscopy.

We demonstrate a compact and self-starting fiber-delivered femtosecond Cr:forsterite laser for nonlinear light microscopy. A semiconductor saturable absorber mirror provides the self-starting mechanism and maintains long-term stability in the laser cavity. Four double-chirped mirrors are employed to reduce the size of the cavity and to compensate for group velocity dispersion. Delivered by a large-mode-area photonic crystal fiber, the generated laser pulses can be compressed down to be with a nearly transform-limited pulse width with 2.2-nJ fiber-output pulse energy. Based on this fiber-delivered Cr:forsterite laser source, a compact and reliable two-photon fluorescence microscopy system can thus be realized.