Threshold Conditions for 1-D Model of Solid-State Laser Cavity Covered with Gold Film

The threshold conditions for the natural modes of a flat-layered solid-state laser model containing a cavity filled in with the gain material are considered. The cavity is assumed to be sandwiched between underlying gold substrate and covered with a gold film (superstrate). We use the Lasing Eigenvalue Problem approach to find the mode-specific frequencies and the corresponding to them threshold gain index values. The results obtained clarify the effect of the gold superstrate thickness on the mode characteristics. This analysis can be used in the laser performance optimization.