A new physical model on lasing in active random media

A new physical model on lasing in active random media is founded. There exist local aperiodic quasi-structure in active random media, and it results in complex localized modes. As the localized modes spatially overlap the localized gain region of active random media, light is amplified in the gain media through stimulated emission. Lasing in active random media is a whole collective effect, and it is due to the interaction of the complex localized modes in active random media with local aperiodic quasi-structure with appropriate pump light. The typical transmission through the active random media with local aperiodic quasi-structure is calculated, and its localized mode is discussed.