LIBS for monitoring the fabrication of optical ceramics

Transparent ceramics are important optical materials with applications in street lightning, high-strength windows, electro- and magneto-optical isolators, high-power laser gain media and radiation detectors. Their fabrication most often relies on powder densification techniques carried out at high temperatures and promoted by dopants, so-called 'sintering additives'. The monitoring of sintering additive concentration, throughout the fabrication process of ceramics, is particularly important in optimizing their effect and maintaining high optical quality and consistency in these materials. Here, we describe the use of Laser-Induced Breakdown Spectroscopy (LIBS) for following the evolution of the concentration levels of silicon in the fabrication of YAG transparent ceramics, a well-known laser material. We have developed an adequate experimental protocol to measured silicon doping in the range of a few hundreds of ppm in test ceramic samples of YAG, and built a calibration curve to quantify it. These results show that LIBS can be reliably implemented for quick assessment of sintering aids in advanced ceramic processing. This work has been funded by the National Institute of Justice and the State of Florida.