Ultrabroadband optical parametric chirped-pulse amplification system, 5; Generation of white-light seed pulses in optical substrates

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

White-light seed pulse for few-cycle optical-parametric chirped-pulse amplification system have been generaged by focusing 80-fs laser pulse from mode-locked oscillator. There were large gaps in the spectral phase of previous white-light generated with photonic-crystal fiber (PCF) for its high-nonlinearity, which limits the minimum compressed pulse duration to 20-30 fs even with adaptive phase control. In this study the white-light was generated by self-phase moduration induced from focusing ultrashort laser pulse on optical substrates. In the experiment, oscillator output pulses with 80-fs duration and 1021 nm center wevelength were parametric-amplified by second harmonics of Yb:YLF CPA system in advance, and focused on optical substrates by microscope objective lens. As a result, broadband white-light pulses from 700 to 1200 nm were generated with 10-10 intensity ratio, which is sufficient for seed pulse for ultrabroadband OPCPA.