Non-normal plane wave electromagnetic scattering from active guiding structures, such as dielectric films, generates large resonances at discrete plane-wave angles of incidence relative to an interface with the active film. These resonances are generated from a "leaky" wave phase matching condition. Enhancement in the scattered field intensities on the order of 100 is achieved using finite diameter pump and probe laser beams and active films as thin as 6 microns. Solid state and dye lasers with unique characteristics are obtained. Oscillators, amplifiers, gyroscopic and nonlinear laser applications employing the active guiding structure or film provide enhanced performance.