Spectral superbroadening of subnanojoule Cr:Forsterite femtosecond laser pulses in a tapered fiber

Spectral superbroadening of subnanojoule femtosecond Cr:forsterite laser pulses is demonstrated for the first time in experiments with a tapered fiber. Coupling $40$-fs $0.6$-nJ pulses of $1.25$-$\mu$m Cr:forsterite laser radiation into a tapered fiber with a taper waist diameter of about $2$ $\mu$m and a taper waist length of $90$ mm, we observed the spectra spanning more than two octaves at the output of the fiber. These experimental results open new horizons for the creation of compact femtosecond systems based on Cr:forsterite lasers and tapered fibers for optical metrology and biomedical applications.