Dipole lasing stimulated by nanoantenna

Theoretically predicted "dipole lasing" as spontaneous excitation of coherent oscillations of dipole momentum of metal nano-particles placed inside or near the surface of the medium with optical amplification. It has close analogy with ordinary lasing, but the polarization of nano-particles stands for the optical cavity mode. Oscillations of polarization cause coherent radiation from nano-particles acting as "nano-antennas". Optical cavity is not necessary, so that the minimum size of the dipole laser can be on the nano-scale. Dipole laser frequency corresponds to the localized plasmon resonance of nano-particles. The manifestation of the dipole lasing is in the divergence of the nano-particle polarisability, that is a second-order phase transition. Threshold conditions, enhancement of the spontaneous emission and optical bistability is dipole lasers are found.