Abstract: A method of controlling a pulsed laser deposition process. A spectroscope is used to acquire Raman response data from a substrate as it is being coated with a film. A processor compares the response data to reference data, which may represent an uncoated substrate or an ideal film. In the former case, the attenuation of the response signal is used to indicate film thickness. In the former case, the peak characteristics of the film can be used to indicate its chemical properties. The processor may be further programmed to compare deposition rates, reaction rates, and transport rates to model data. The processor makes decisions regarding equipment control based on these comparisons. It may access heuristic rules to aid in decision making where several factors are involved.