Abstract: Disclosed is an evanescent-wave-coupled microcavity laser in which a gain medium is positioned outside a circularly symmetric microcavity having a size of a few tens of microns to a few hundreds of microns to generate a laser oscillation using a gain medium existing in the evanescent-field of a resonance mode. Particularly, a gain medium containing a semiconductor, atoms, molecules, or quantum dots is placed outside the microcavity where the evanescent-wave of the microcavity mode exists, to be excited by an electric or an optical pumping. Fluorescence irradiated from the excited gain medium is coupled with the evanescent-wave of the resonator mode to obtain a gain, so that amplification of light is triggered. The amplified light circulates inside the microcavity through total internal reflection to induce a stimulated emission of radiation from the excited gain medium in the field of evanescent-wave so that a stable laser oscillation is established.