Optics and Quantum Electronics 1. 5fs Pulses and Octave-Spanning Spectra from a Ti:sapphire Laser Oscillator Sponsors AFOSR Project Staff

The laser set-up is shown in Figure 1. Specially designed pairs of double-chirped mirrors [1] compensate for higher-order as well as second-order dispersion, and CaF2 prisms permit dispersion adjustment. A 2.7-mm-thick Ti:sapphire crystal is pumped with about 4 W of cw 532 nm power. After modelocked operation is initiated by translating the prism P1, a steady state output power of about 120 mW can be obtained. Shorter pulses and additional spectral width are achieved with the added focus in a 2.4 mm thick plate of BK7 glass. Without this additional focus, saturation of the KLM effect in the Ti:sapphire crystal limits the amount of spectral broadening due to self-phase modulation as well. Our cavity is therefore designed to produce a short pulse and strong self-phase modulation but less of a Kerr-lensing effect in the second focus.