  We perform one- and two-photon high resolution spectroscopy on ultracold
samples of RbCs Feshbach molecules with the aim to identify a suitable route
for efficient ground-state transfer in the quantum-gas regime to produce
quantum gases of dipolar RbCs ground-state molecules. One-photon loss
spectroscopy allows us to probe deeply bound rovibrational levels of the mixed
excited (A1{\Sigma}+ - b3{\Pi}0) 0+ molecular states. Two-photon dark state
spectroscopy connects the initial Feshbach state to the rovibronic ground
state. We determine the binding energy of the lowest rovibrational level
|v"=0,J"=0> of the X1{\Sigma}+ ground state to be DX 0 = 3811.5755(16) 1/cm, a
300-fold improvement in accuracy with respect to previous data. We are now in
the position to perform stimulated two-photon Raman transfer to the rovibronic
ground state.
