Generation of infrared photon pairs by spontaneous four-wave mixing in a CS₂-filled microstructured optical fiber

We experimentally demonstrate frequency non-degenerate photon-pair generation via spontaneous four-wave mixing from a novel CS₂-filled microstructured optical fiber. CS₂ has high nonlinearity, narrow Raman lines, a broad transmission spectrum, and also has a large index contrast with the microstructured silica fiber. We can achieve phase matching over a large spectral range by tuning the pump wavelength, allowing the generation of idler photons in the infrared region, which is suitable for applications in quantum spectroscopy. Moreover, we demonstrate a coincidence-to-accidental ratio of larger than 90 and a pair generation efficiency of about \(10^{-2}\) ${10}^{-2}$ per pump pulse, which shows the viability of this fiber-based platform as a photon-pair source for quantum technology applications.