Multiphysical simulation approach to specify material properties of additively manufactured laser heat sinks: Potentials and challenges

Regulating heat inside diode pumped Nd:YAG laser crystals is still challenging in many laser applications. The laser induced thermal expansion often stresses the laser medium to its mechanical limits. One approach to dissipate the heat from the laser medium is to imprint crystals into a heat sink, to improve the thermal connection between the two components. The development of printing materials makes it possible to influence their properties in addition to the thermal and mechanical requirements. This paper presents a simulation approach to investigate the correlation between material properties of an additively manufactured heat sink and mechanical stress inside the laser crystal. By predefining the permitted printing material properties for a given output power of the laser diode, a non-destructive operation can be achieved. Based on a realistic multiphysical simulation model of the laser pumping process, which includes optical, thermal and mechanical boundary conditions, potentials and challenges for the development of tailored 3D printable materials are explored.