Neodymium random laser with external mirrors

We have studied the influence of the front and the rear mirrors on the emission properties of neodymium random lasers at different thicknesses of the powder layer. Introduction of external mirrors drastically reduces the lasing threshold of the random laser, with the effect of the front mirror being more dominant. External mirrors also influence the location of the stimulated emission region within the powder volume. The experimental results are in a good agreement with the results of the Monte-Carlo simulation.