Fiber free all solid state multipass spectral broadening down to 10 fs Fourier limit

Summary form only given. Spectral broadening techniques based on fibers are prone to damage and are sensitive to alignment, especially when high average (>50 W) and high peak powers (>10 MW) are combined. Broadening techniques in bulk material [1, 2] represent an alternative approach. However, until recently these techniques were limited in efficiency, beam quality and bandwidth. A lately demonstrated concept of multipass spectral broadening in a waveguide-like geometry [3] showed that high efficiency and excellent beam quality can be reached simultaneously. Here we show further that the bandwidth can be extended down to 10 fs in Fourier transform limit (FTL), while still preserving high efficiencies of 70% and good beam quality (see Fig 1c). Proper dispersion management plays a crucial role in this process. This progress paves a way to all solid state, compact and robust diode pumped laser-oscillators for attosecond pulse and XUV generation with MHz repetition rate.