  We propose a new type of Feshbach resonance occurring when two different
ultracold atoms in their ground state undergo an s-wave collision in the
presence of a continuous-wave laser light. The atoms collide in the
dissociation continuum of the molecular electronic ground state which is
coupled by the light to a rovibrational level of the same electronic ground
state: we name this a Laser-Assisted Self-Induced Feshbach Resonance (LASIFR).
This mechanism, valid for all polar molecules, is analyzed on the example of
ultracold 87Rb and 84Sr atoms, for which the laser frequency falls in the THz
range. The control of the LASIFR with the laser frequency and intensity allows
for a strong increase of the pair probability density at short distances, which
tremendously increases the number of atoms pairs transfered toward the absolute
ground state level by STImulated Rapid Adiabatic Passage (STIRAP). The LASIFR
results in the observation of a standard Fano profile in the pump transition of
the STIRAP process, and is also promising for the optical control of the
interspecies scattering length without atom losses.
