<p dir="ltr">Simulated FDTR phase lag data for a gold on sapphire sample, for a range of possible values of 4 input parameters (laser spot size, substrate thermal conductivity, gold layer thickness, and interface thermal conductance). This dataset contains the primary simulation data of a research project, however it will not contain every post-processing file associated with the research. That will instead be stored on an associated GitHub repo, which will be linked here after it has been fully created. The data in this submission is analyzed and discussed in an associated research manuscript which is in preparation for submission.</p><p dir="ltr"><br></p>