title: High purity bright single photon source.
abstract: Using cavity-enhanced non-degenerate parametric down-conversion, we have built a frequency tunable source of heralded single photons with a narrow bandwidth of 8 MHz, making it compatible with atomic quantum memories. The photon state is 70% pure single photon as characterized by a tomographic measurement and reconstruction of the quantum state, revealing a clearly negative Wigner function. Furthermore, it has a spectral brightness of ~1,500 photons/s per MHz bandwidth, making it one of the brightest single photon sources available. We also investigate the correlation function of the down-converted fields using a combination of two very distinct detection methods; photon counting and homodyne measurement.
authors: J S
authors: JS
authors: Neergaard-Nielsen
authors: B M
authors: BM
authors: Nielsen
authors: H
authors: H
authors: Takahashi
authors: A I
authors: AI
authors: Vistnes
authors: E S
authors: ES
authors: Polzik