Group-velocity-matched second-harmonic generation: An efficient scheme for femtosecond ultraviolet pulse generation in periodically domain-inverted β-BaB2O4

With the combined use of the group-velocity-matched and the quasi-phase-matched frequency doubling in β-BaB2O4, femtosecond ultraviolet pulse generation is found to be realizable with high efficiency. Calculation of the group-velocity mismatch shows that at ∼630 nm wavelength of the pump pulse the mismatch vanishes completely. Typical design parameters such as the walk-off length, the dispersion lengths, and the quasi-phase-matching period are evaluated numerically around the zero walk-off wavelength. Temperature tuning of the operation wavelength is investigated as well.