Self-distributed feedback lasing in a system of cold atoms

We present a semiclassical anal sis of lasing with an injected signal in a system of cold two-level atoms where the effects of atomic recoil are inclu ded self-consistently. This analysis predicts that the atoms may bunch unde r the effects of dipole forces to produce a density grating. This grating p roduces distributed feedback which can induce lasing action even when the g ain of the atomic medium is less than the cavity losses.