Efficient ultrafast frequency conversion sources for the visible and ultraviolet based on BiB3O6

Efficient frequency conversion of high- repetition-rate femtosecond and picosecond pulses with wide tunability throughout the visible, blue, and UV is demonstrated in the nonlinear optical crystal BiB3O6 (BIBO). Using direct single-pass second harmonic generation of Kerr-lens-mode-locked Ti:sapphire laser, average output powers close to I W at conversion efficiencies in excess of 50% are demonstrated with broad spectral coverage across 370-450 nm in the near-UV and blue spectral range. Output pulse durations of 220 fs and 2.8 ps have been obtained at a pulse repetition rate of 76 MHz. By implementing a synchronously pumped femotsecond optical parametric oscillator (OPO) based on BIBO, the generated spectral range is further extended to cover the entire visible spectrum, across the green-yellow-orange-red regions. Average output powers of up to 270 mW in pulses of 120 fs at 76 MHz repetition rate have been generated across the 480-710 Am range. Internal frequency doubling of the visible OPO signal pulses in the crystal of O-BaB2O4 has permitted high-repetition-rate ferntosecond pulse generation with wide tunability across 250-350 nm in the UV at up to 100 mW of average power. The potential of BIBO for efficient frequency conversion of high-intensity pulses is also demonstrated through third harmonic generation of amplified microjoule picosecond pulses at 1064 nm. Output pulse energies of 216 mu J in 29 ps duration at 25 Hz repetition rate have been obtained at355 nm with overall conversion efficiencies of up to 50%.