We propose an optica1-terahertz link using a triply-resonant photonic molecule and discuss its applications for terahertz signal detection and synthesis using traditional RF and optical techniques. Our design is a low-cost alternative to THz frequency generation via microwave drives and can be operated in both continuous-wave and pulsed regimes.

We present a dual-functional integrated chip realized on a thin-film lithium niobate platform, serving as both terahertz emitter and detector, enabling broadband emission and detection from 0.1 to 2.5 THz.

We report on the fabrication and characterization of a Fabry-Perot microcavity enclosing a thin diamond membrane at cryogenic temperatures. The cavity is designed to enhance resonant emission of single nitrogen-vacancy centers by allowing spectral and spatial tuning while preserving the optical properties observed in bulk diamond. We demonstrate cavity finesse at cryogenic temperatures within the range of F ¼ 4000–12 000 and find a sub-nanometer cavity stability. Modeling shows that coupling nitrogen-vacancy centers to these cavities could lead to an increase in remote entanglement success rates by three orders of magnitude.

Coupling nitrogen-vacancy (NV) centers in diamonds to optical cavities is a promising way to enhance the efficiency of diamond-based quantum networks. An essential aspect of the full toolbox required for the operation of these networks is the ability to achieve the microwave control of the electron spin associated with this defect within the cavity framework. Here, we report on the fabrication of an integrated platform for the microwave control of an NV center electron spin in an open, tunable Fabry–Pérot microcavity. A critical aspect of the measurements of the cavity’s finesse reveals that the presented fabrication process does not compromise its optical properties. We provide a method to incorporate a thin diamond slab into the cavity architecture and demonstrate the control of the NV center spin. These results show the promise of this design for future cavity-enhanced NV center spin-photon entanglement experiments.