Exclusive anti-stokes raman scattering using coherent material excitation

A new process capable of scattering intense anti-Stokes waves that uses stimulated electronic Raman scattering in metal vapor is proposed. The coherent material excitation produced by a prepump pulse couples with the forthcoming main pulse exclusively to create polarization that radiates the anti-Stokes wave. The selection rule governed by angular momentum conservation is the key to cause such strong coupling to induce unidirectional upconversion without any population inversion. The power conversion efficiency from the pump wave to the anti-Stokes wave is theoretically expected to reach 100% in this process.