High efficiency single photon detection via frequency up-conversion

TLDR

Up-converting infrared photons to visible wavelengths in a nonlinear crystal allows the use of silicon avalanche photodiodes, which have higher detection efficiencies than traditional IR band APDs. The authors propose a single‑photon detection scheme that up‑converts IR photons to visible light for higher efficiency and lower noise, and a two‑crystal extension enabling coherent up‑conversion of orthogonal polarizations for complete quantum state transduction. They employ a periodically poled lithium niobate crystal pumped by a pulsed 1064 nm Nd:YAG laser to convert 1550 nm photons to 631 nm, and extend the setup with a second crystal for coherent polarization up‑conversion. The system achieves up to ~80 % conversion efficiency, scales to single‑photon detection, and maintains a dark‑count rate of 3 × 10⁻⁴ per count.

Abstract

Abstract We propose a method of single photon detection of infrared (IR) photons at potentially higher efficiencies and lower noise than allowed by traditional IR band avalanche photodiodes (APDs). By up-converting the photon from the IR, e.g. 1550 nm, to a visible wavelength in a nonlinear crystal, we can utilize the much higher efficiency of silicon APDs at these wavelengths. We have used a periodically poled lithium niobate (PPLN) crystal and a pulsed 1064 nm Nd:YAG laser to perform the up-conversion to a 631 nm photon. We observed conversion efficiencies as high as ∼ 80%, and demonstrated scaling down to the single photon level while maintaining a background of 3 ×s; 10−4 dark counts per count. We also propose a 2-crystal extension of this scheme, whereby orthogonal polarizations may be up-converted coherently, thus enabling complete quantum state transduction of arbitrary states.