Microwave controlled efficient Raman and sub-Raman generation

We propose an efficient scheme for the generation and the manipulation of Raman fields in an homogeneously broadened atomic vapor in a closed three levels $\Lambda$-configuration. The key concept in generating the Raman and sub-Raman fields efficiently at lower optical densities involve the microwave induced atomic coherence of the lower levels. We show explicitly that, generation efficiency of the Raman fields can be controlled by manipulating the coherences via phase and amplitude of the microwave field.