Martin Huonker

Passive cooling effects of low and high fill-factor 937 nm 1 cm arrays

Diode-pumped solid-state lasers are gaining acceptance as the desired laser source for materials processing as well as a host of new applications that are expanding rapidly. Because of this, the performance, stability and lifetime of the diode-pump source face unprecedented scrutiny. Increasing the lifetime of the diode, while increasing power, remains a primary focus of the industry. One lifetime limiting issue is that of a voltage potential in the water cooling channels which can cause cooler degradation and lower efficiency over time. Studies have been carried out that explore different cooling approaches based on passive schemes where insulation layers are present to shield the voltage from the water channels. However, with the introduction of insulation layers, a reduction of the deployable power from that of microchannel coolers is seen. This report explores the effects of passive cooling approaches on the power and divergence of 1 cm AuSn/CuW mounted bars with fill factors ranging from 10% to 50%. It is shown that a 150 W array can be realized on a passive cooler and multiplexed to give a 1600 W stack. Thermal modeling is presented along with life-test data for passively cooled devices.