LAUSR

We have demonstrated amplified spontaneous emission (ASE) propagating along the planar interface between two adjacent dielectrics with slightly different refractive indexes. This emission originates from the leaky mode, fueled by optical gain in the low-index dielectric, that is outcoupled to the high-index dielectric in vicinity of the critical angle for total internal reflection. This led us to the observation of spectacular concentric rings of ASE emission occurring above the low and soft stimulated emission threshold. The results of our study can be used to develop novel miniature low-threshold stimulated emission sources and photonic circuits operating at optical frequencies.