Modification of laser gain properties through local-field effects and nanostructuring

We have recently developed a simple phenomenological model that allows one to account for the modifications of the gain characteristics of nanocomposite optical materials with specific geometries. Here we give a generalized formulation of our model to show that it can be applied to a broad variety of composite geometries. We demonstrate the application of our model using the Maxwell Garnett composite geometry with the resonant molecules in its host, which represent a practically important case that has not been treated earlier. We also give numerical examples for the Maxwell Garnett composite geometry with the resonances in either host or inclusions, and find the conditions under which it is possible to achieve an enhancement or suppression of the small-signal gain coefficient compared to its value in a bulk material. Using our simple model, one can identify the set of parameters, exhibiting the desired changes to the gain characteristics, prior to or instead of performing a more precise computationally intensive analysis.