Optical parametric oscillator produces 13-fs pulses

Optical parametric oscillator produces 13-fs pulses

Researchers at the Ecole Polytechnique (Palaiseau, France) have generated 13-fs pulses from a b-barium borate (BBO) optical parametric oscillator (OPO) pumped by a frequency-doubled titanium-doped sapphire (Ti:sapphire) laser. The system is tunable from 590 to 666 nm, with an average output power of 130 mW at 640 nm. The folded six-mirror ring-cavity design includes a pair of fused-silica prisms to compensate for grou¥delay dispersion. A 2-W Ti:sapphire laser (Spectra-Physics, Mountain View, CA) produces 90-fs pulses at an 82-MH¥repetition rate. Prior to injection of pulses into the OPO cavity, the 400-nm second harmonic is generated by a 2-mm crystal of BBO. All cavity mirrors are 99.5% reflective, centered at 630 nm, and the OPO output coupler is 7% transmissive. Wavelength is actively stabilized to within 5% of linewidth by a piezoelectric actuator that controls cavity length by shifting the output coupler.