Inversionless lasing with self-generated driving field - art. no. 013814

We propose and study resonant ladder schemes of inversionless lasing on a f ast-decaying transition when the population inversion is not possible or Ve ry difficult to achieve. The driving field on a neighboring, slowly decayin g transition is not imposed externally, but is self generated in the same a ctive medium. Inversionless lasing in such schemes avoids the problem of dr iving-field absorption and leads to considerable reduction in the required pumping rate. Applications of such schemes include inversionless ultraviole t and soft x-ray lasing in gas lasers and inversionless generation of coher ent mid/far-infrared emission on intersubband (interlevel) transitions in m ultiple quantum-well or quantum-dot laser diodes.