Broadband OPCPA pumped by ultra-narrowband gaseous iodine laser

Amplification of femtosecond pulses using an ultra-narrowband gaseous pulse laser was demonstrated for the first time. A single-shot sub-nanosecond iodine photodissociation laser with a bandwidth of 20 pm was used as a driver in an all-stage OPCPA. An externally triggerable OPO tuned to laser line of 1315.24 nm was used in the front end of the iodine laser. Frequency tripled beam at 438 nm was used to pump parametric amplifiers, LBO and KDP crystals. The signal pulses from a Ti:sapphire laser at the central wavelength of 800 nm with a bandwidth of 70 nm (FWHM) were stretched from 12.5 fs to 250 ps and amplified by a factor of 2x10(8). The amplified pulses of typical bandwidth of 50 nm were compressed down to 27 fs. The output power of 0.5 TW was achieved. An optimized amplifier chain and addition of a third nonlinear crystal would enable to generate femtosecond pulses of several terawatts. The broadband pulses at 800 nm central wavelength were amplified in the KDP crystal for the first time, due to the suitable wavelength of the pump pulses. Availability of large aperture KDP crystals promises the generation of petawatt beam at kJ iodine laser facilities.