Coherent frequency conversion for quantum information processing

Efficient frequency conversion is crucial for interfacing photons with a variety of quantum systems ranging from matter qubits (color centers, quantum dots, atoms), optical fibers, detectors, that often operate at widely different wavelengths. Frequency conversion is also a resource to process quantum information.1,2 Parametric processes such as sum frequency generation (SFG) and Bragg scattering four wave mixing (BS-FWM) offer a good versatility for such frequency conversion. It is well understood that those nonlinear processes have to be strong enough and satisfy phase matching to achieve a high conversion efficiency. While it is enough to consider those two aspects for moderate conversion efficiency up to 50%, the analysis is a bit more complicated when targeting efficiencies closely approaching unity. We are reviewing the pitfall that must be avoided to indeed reach near unity frequency transduction.SCOPUS: cp.p