Vacuum ultraviolet application of Li2B4O7 crystals: generation of 100 fs pulses down to 170 nm

A newly developed nonlinear crystal belonging to the borate family, lithium tetraborate Li2B4O7 (LB4), has excellent properties below 180 nm and allows the generation of wavelengths down to 170 nm with an all-solid state laser system. This was gleaned from a characterization of the newly grown crystal by the Czochralski method. A comparison with a lithium triborate sample showed that it performs better in the vacuum ultraviolet spectral region below 180 nm. Its effective nonlinearity is maximized under the conditions of 90 degree-phase matching.