Yb:KYW Innoslab-amplifier

Amplification by Innoslab amplifiers has been applied to ultrafast laser pulses for many years. Recent progress in high power laser diodes and a new pumping scheme made application of ytterbium doped laser crystals which support subpicosecond pulse durations possible. Ultrashort pulse experiments were carried out with a Yb:KYW fs-oscillator (HighQ Laser Innovation GmbH).To enable shorter pulse lengths tungstates (KYW, KGW) have been applied as laser hosts as they exhibit a broader emission bandwidth. Calculations took a three dimensional model of the laser crystal including the distribution of pump and seed radiation and temperature dependence of inversion of the ytterbium ion into account. Arbitrarily distributed electromagnetic fields are propagated solving the Fresnel Huygens diffraction integral. Due to the lower gain cross section of Yb:KYW expected output powers are below the values achieved with Yb:YAG but with significantly reduced gain narrowing. First experimental results in comparison to these calculations will be presented.