Fast and power-efficient infrared single-photon upconversion using hot-carrier luminescence

We analyze a new method for single-photon frequency upconversion. This technique uses a byproduct of the avalanche process - electroluminescence resulting from hot-carrier recombination - as a means of upconversion. Because the spectrum of the emitted photons peaks near the bandgap of the multiplying material and has a significant tail at higher energies, it is possible to generate secondary photons at significantly higher energies than the primary absorbed photon. The secondary photons can then be detected by a coupled CMOS silicon single-photon avalanche diode (SPAD), where the information can also be processes. This upconversion scheme does not require any electrical connections between the detecting device and the silicon SPAD, so glass-to-glass bonding can be used, resulting in inexpensive, high-density arrays of detectors. We calculate the internal and system upconversion efficiencies, and show that the proposed scheme is feasible and highly efficient for application such as quantum key distribution and near infrared low-light-level imaging.