Spectral transformation of infrared ultrashort pulses in laser crystals

• Transformation of femtosecond pulses in laser crystals.
• Generation of supercontinuum in selected single crystals.
• Effect of material bandgap on the supercontinuum generation.

The impact of peculiarities of transparent media on the self transformation of femtosecond pulses is considered. Spectral width and intensity distribution of anti-Stokes part of supercontinuum generated by infrared femtosecond pulses in selected single crystals were determined for different pulse energy density as a function of incident pulse wavelength changed in the 800–1600 nm region. Effect of material bandgap on the supercontinuum generation was examined based on experimental data for single crystals of gadolinium orthosilicate, gallium gadolinium garnet, lithium tantalate and lutetium vanadate. It was found that the anti-Stokes part of supercontinuum generated in Gd2SiO5 and Gd3Ga5O12 crystals has a quite large spectral width with a short wavelength cut-off around 450 nm and contains a broad plateau.