This project supports the collaboration of Drs. Robert Boyd, J. H. Eberly, and E. Wolf from the University of Rochester, and Dr. J. Cooper of the University of Colorado, with Drs. G.S. Agarwal, S. Dutta Gupta, S. Ravi, and S.P. Tewari of the University of Hyderabad in India. The research will address the following areas: lasers without population inversion; stimulated dielectronic radiative recombination; nonlinear optical phenomena in partially coherent fields; higher-order nonlinearities in the interaction of radiation with matter; interaction of atoms with radiation in a cavity; four-wave mixing lineshape calculations beyond the impact approximation; and quantum noise in phase conjugation. The collaboration will involve three three-month visits by the Indian scientists to the U.S. and four one-month visits by the U.S. scientists to India. Scope: The project continues successful collaboration that started between the two groups several years ago. This past collaboration have produced a number of new results in theoretical quantum optics which are documented in published papers. The project is of significant interest to the U.S. and Indian science, and is well within the objectives of the U.S.-Indian Cooperative Science Program. This project is being funded under two grants INT-9100685 to the University of Hyderabad, P.I. Dr. G. S. Agarwal and INT-9017532 to the University of Rochester, P.I. Dr. Robert Boyd.