A Kilowatt Yb:YAG Thin-Disk Amplifier Sized by Axial Heat Flow and Thermal-Lens Power

This paper presents a computed design for a diode-pumped Yb:YAG thin-disk amplifier head intended for kilowatt-class average power at 1030 nm. The sizing follows from applying the relevant intensity, thermal, nonlinear and geometric bounds at a single stated operating point, with every number produced by a deposited computation. The headline result is an absorbed pump power of 1080 W, a heat load of 181 W, an output of 899 W (74.9% of incident pump), an axial temperature drop across the disk of only 56.8 K, and a pump intensity of 1.9 kW/cm2 over a 0.64 cm2 pumped area. The binding constraint is identified explicitly: disk bending under the axial temperature drop and amplified spontaneous emission in the high-gain disk plane. The design is SIMULATED, NOT MEASURED: no hardware was built for this study, and all performance figures are predictions from stated assumptions, offered as a basis for a build decision and a measurement plan.