Ultra-broadband optical parametric chirped-pulse amplification pumped by an Yb:YLF chirped-pulse amplification laser

Akahane, Yutaka; Aoyama, Makoto; Ogawa, Kanade; Tsuji, Koichi; Sugiyama, Akira; Yamakawa, Koichi; Kawanaka, Junji*; Harimoto, Tetsuo*; Nishioka, Hajime*; Fujita, Masayuki*

We have confirmed ultra-broadband optical-parametric amplification (OPA) over 200 nm pumped by one beam of Yb:YLF CPA laser at degeneracy. A white light seed pulse with a bandwidth of 400 nm is generated by the 80-fs duration mode-locked pulse, that was identical to seed pulse for the Yb:YLF CPA pump laser, through a photonic crystal fiber, and then temporally stretched to -2 ps by passing through a glass block and injected to the BBO crystal at an internal crossing angle of 0.6 degree. The pump pulse with 3ps pulse duration was down-collimated and used to pump the crystal with an energy of 1.1 mJ. As a result, we have observed an ultra-broadband amplification over 200nm. The OPA gain was measured to be -10, which corresponds to sub-100 J energy of amplified signal pulse. With injecting second pump pulse with a different internal crossing angle of 1.2 degree, our OPCPA could amplify the 400 nm bandwidth which supports the intense few-cycle pulse generation.