Generation of ultra-broadband high energy pulses without external amplification

We report on the generation of ultra-broadband radiation utilizing the Chirped-pulse oscillator (CPO) concept. With this technique, pulse energies in excess of 150 nJ could be obtained directly out of a Kerr-lens-mode-locked Ti:sapphire oscillator. By spectral broadening of these pulses in a standard single-mode fiber, output spectra corresponding to a Fourier-limited pulse duration of 5,7 fs: at an energy of 50 nJ have been achieved. Due to the corresponding high peak intensity approaching 10 MW, direct measurement of the carrier-envelope phase of the pulses is feasible.