Lasing without inversion in a V system due to trapping of modified atomic states

We analyze lasing without inversion in a V system driven by a single optical field. This is shown to depend on the relaxation rates and photon degeneracy parameters of the system and occurs for a broad range of lasing intensities. The physical mechanism is explained in terms of trapping of the modified ground state, which is coherently split by the optical pump field. © 1992 The American Physical Society.