  We propose a scheme to couple short single photon pulses to superconducting
qubits. An optical photon is first absorbed into an inhomogeneously broadened
rare-earth doped crystal using controlled reversible inhomogeneous broadening.
The optical excitation is then mapped into a spin state using a series of
$\pi$-pulses and subsequently transferred to a superconducting qubit via a
microwave cavity. To overcome the intrinsic and engineered inhomogeneous
broadening of the optical and spin transitions in rare earth doped crystals, we
make use of a special transfer protocol using staggered $\pi$-pulses. We
predict total transfer efficiencies on the order of 90%.

Quantum Physics