LiF, an underestimated supercontinuum source in femtosecond transient absorption spectroscopy.

We present supercontinua generated in LiF and CaF(2) revealing that LiF is advantageous especially in the near UV region since it pushes the cut-off wavelength about 17 nm towards lower wavelengths and the occurrence of color centers, which has been considered as a drawback up to now, is not a limitation for its applicability in femtosecond transient absorption spectroscopy. Even though the color centers occur within a short time of illumination, they do not influence the supercontinuum generation significantly and they can furthermore, if desired, be eliminated from the substrate simply by heating. Thus LiF is a promising substrate for broad band measurements in the UV/vis range.