95-fs Yb:Lu2O3 Thin-Disk Laser Operating at 21 W Average Power

Summary form only given. High-power laser oscillators in the sub-100-fs pulse duration regime at megahertz repetition rates are compact and reliable alternatives to multi-stage amplifier systems. Sub-100-fs bulk oscillators based on Ti:sapphire - the working horses in ultrafast science - are currently limited to 3.5 W of average power. In comparison, sub-100-fs bulk oscillators based on other gain materials have already reached 12.5 W. However, thermal effects in the gain material are a severe challenge for further power-scaling [Fig. 1(a)]. The thin -disk geometry is advantageous for higher average powers as it reduces thermal effects in the gain material. Ultrafast thin -disk laser (TDL) oscillators generated up to 275 W at 583 fs pulse duration. However, high average power operation in the sub-100-fs regime still remains challenging. In 2017, we presented an Yb:Lu203 TDL oscillator generating 10.7 W average power in 88-fs pulses. Here, we investigate power-scaling of a Kerr lens mode -locked (KLM) Yb:Lu 2 0 3 TDL oscillator operating in the sub-100-fs pulse duration regime. Implementing a double pass on the disk and optimizing the operation parameters [Fig. 1(b)] enabled us to increase the output power by a factor of two and the optical-to-optical efficiency by a factor of three compared to our previous result.