Abstract

In high-peak-power diode-pumped solid-state laser systems, diode chirp and sag during the pump pulse can play a major role in determining the pump energy absorbed in the laser medium. For pulse durations, 10 < τ < 1000 μs, typically used for diode-pumped solid-state lasers, we find that transient output power and wavelength chirp of high-peak-power laser-diode bars can be modeled assuming one-dimensional heat flow and linear temperature dependences for chirp and efficiency. The model is in good agreement with experimental data for Si heatsink mounted 940 nm laser-diode bars operating at an initial power of 100 W/cm. The figure-of-merit for a heatsink material in this application is (ρC_pK)^1/2 where ρC_p is the volumetric heat capacity and K is the thermal conductivity. As an example of the utility of the derived expressions, we determine an effective absorption coefficient as a function of pump pulse duration for a diode-pumped solid-state laser utilizing Yb:Sr₅(PO₄)₃F (Yb:S-FAP) as the gain medium.

© 1998 Optical Society of America