Atomistic modeling study of surface segregation in Nd:YAG

This study investigates the composition of free surfaces of neodymium-doped yttrium-aluminum-garnet, using energy minimization techniques. Atomistic modeling shows that the dopant is concentrated in a zone within 5 angstrom of the surface, the enrichment factor being around 1300 when comparing surfaces with bulk concentrations. It is shown that the (111) surface can incorporate 1.8 times as much Nd as the (110) surface, the latter commonly found in YAG morphologies. Our results indicate that by using nanocrystalline ceramics and by modifying crystal growth to form (111) surfaces, the Nd content and thus the laser power may be significantly increased.