  We show that the probability of the collision-induced absorption of
non-resonant microwave photons by a gas of ultracold molecules is dramatically
enhanced near a Feshbach scattering resonance. This can be used for detecting
Feshbach resonances of ultracold molecules by measuring the microwave field
absorption and for tuning the elastic scattering cross sections of ultracold
molecules by varying the frequency and intensity of the microwave field in a
wide range of the field parameters.
