Stimulated emission of radiation using spin-population inversion in metals

The discovery of masers and lasers has led to major breakthroughs in science and technology. Later important developments include compact semiconductor lasers for visible to near-infrared and quantum-cascade lasers for far-infrared to THz radiation. In conclusion, we have fabricated ballistic-range magnetic point contact arrays integrated in IR-THz range metal-oxide resonators and observed threshold-type I-V excitations of giant magnitude, correlated with optical emission from the devices, consistent with the expected spin-flip laser effect in the system.