Tunable Thermal Lensing Enabled by Silicate Bonding of Sapphire to SESAMs: Novel Devices for High-Power Lasers

High-power ultrafast laser sources are widely used for industrial applications and scientific research. The leading technology to reach high average powers directly from ultrafast oscillators are SEmiconductor Saturable Absorbed Mirror (SESAM) modelocked Thin-Disk Lasers (TDLs), with average powers up to 350 W [1] . When power-scaling TDLs, thermally induced lensing, especially in the SESAM, is one of the key challenges that needs to be addressed. For this reason, many strategies to reduce the thermal lensing of the SESAM have been investigated, such as thinner substrates, improved contacting [1] , or substrate transfer followed by etching [2] .