  We demonstrate a novel method of inducing an optical Feshbach resonance based
on a coherent free-bound stimulated Raman transition. In our experiment atoms
in a Rb87 Bose-Einstein condensate are exposed to two phase-locked Raman laser
beams which couple pairs of colliding atoms to a molecular ground state. By
controlling the power and relative detuning of the two laser beams, we can
change the atomic scattering length considerably. The dependence of scattering
length on these parameters is studied experimentally and modelled
theoretically.
