Abstract
Electro-optic upconversion in microresonators has been explored for shifting microwave photons (~10 GHz) into the optical domain for linking qubits for communication in a quantum network. There has also been interest in detecting photons at higher frequencies in the terahertz domain (>0.1 THz) particularly for applications in radio astronomy and earth observation. Here, I present the experimental demonstration of multichannel upconversion of signals that are an octave higher than previously demonstrated. The scheme involves the optical signals being resonant in a whispering gallery mode resonator made of lithium niobate. It shows multichannel detection at a photon number efficiency of 2.5E-6 photons per milliWatt of pump power at 0.16 THz. For higher sensitivity, the device can be implemented with the terahertz field being resonant as well.