Efficient Conversion from Atomic Spin Wave to Single Photon with Controllable Temporal Length

Abstract The single photons with controllable temporal length are essential to connect various heterogeneous nodes in quantum networks. The spontaneous Raman scattering (SRS) process in atomic ensembles is a candidate for generating heralded single photon sources. However, efficient conversion from atomic spin waves to single photons with controllable temporal length has not yet been demonstrated experimentally. Here SRS is used in a cold atomic ensemble to generate Stokes photons, which herald the generation of the correlated atomic spin waves. By applying read pulses with adjustable duration to the atoms, the spin waves are converted to heralded single photons (anti‐Stokes photons) with controllable temporal length. The conversion efficiency from atomic spin waves to anti‐Stokes photons is improved by utilizing cavity enhancement. The heralded single photons are proved to be nonclassical and to be in a pure state when the photon duration ranges from 100 ns to 3 µs. The conversion efficiency of photons from atomic spin waves is () for the anti‐Stokes photon duration of 3 µs (100 ns). The research offers an experimental foundation for the interconnection of heterogeneous quantum nodes.