Efficient, high-power, all-buIk spectral broadening in a quasi-waveguide

The bandwidth of gain materials for high-power femtosecond lasers, mainly Yb:YAG, is fairly limited, allowing only > 100 fs long pulses to be generated efficiently in oscillators [1] or near ps pulses from amplifiers [2]. Therefore, additional pulse-compression, commonly employing solid or gas-filled fibres, is necessary to permit e.g. compact, MHz XUV sources [3] or brilliant mid-infrared (MIR) sources for spectroscopy applications [4]. The use of bulk materials offers some distinct advantages over fiber-based spectral broadening such as insensitivity to coupling or alignment as well as low cost.