Single-photon THz-sensing using 4-wave mixing in cooperative Rydberg arrays

While several, physically interesting sources of THz radiation exist, sensing in this regime, particularly at the single-photon limit, poses a challenge. Especially, when coherence information are to be preserved. We theoretically investigated a terahertz detection technique that utilizes four-wave mixing in atomic Rydberg arrays to transduce incoming terahertz photons to optical frequencies. In such arrays cooperative effects can strongly enhance the light-matter coupling and direct the incident light. We find that, using specific resonance conditions, our scheme efficiently transduces incoming THz radiation to the optical domain, while scattering into specific in-plane modes which can then be coupled to detectors or optical fibers for further processing. This opens up interesting directions such as coupling of several such devices for quantum sensing applications.