- The existence of odd Raman subharmonics in the nonlinear mixing of fields of frequencies l and s is examined in a nonperturbative way. It is shown that the coupling of Stokes and anti-Stokes processes at high pump powers produces odd subharmonics in nonlinearly generated signals. It is also shown that this coupling can lead to gain at the odd subharmonics. An effective Hamiltonian is used to discuss the coupling of Stokes anti-Stokes processes. Numerical results showing the odd subharmonics are presented. The origin of odd subharmonics in terms of transitions among dressed states is also discussed. 1991 The American Physical Society.