Abstract

The enhancement of coherent light amplification in the higher frequency regime via the application of one or several external lower frequency fields is by now a well-established phenomenon, especially in lasing without inversion¹⁻² and resonant four-wave mixing.³ A particularly useful picture for understanding the underlying physics of these processes is in the basis of the eigenstates of the full Hamiltonian, which includes both the atom plus the applied strong laser fields (the so-called dressed states). Here, trapping of ground state population in one of these dressed states and gain due to “hidden inversions” between dressed states has been identified as one of the main mechanisms of lasing without inversion.²

© 1998 Optical Society of America