My research topic is frequency up-conversion of ultrashort IR laser pulses into visible and UV spectral range, in a form of numerical simulations and experiments. Nonlinear optical crystals are used to convert wavelengths of lasers developed at HiLASE Centre. Beside standard conversion, where the goal is to reach as high conversion efficiency as possible, I am also interested in nonlinear pulse shaping caused by back-conversion processes. This allows one to obtain much shorter pulses at harmonic frequencies, than are the pulse durations at fundamental frequency.