Narrow-linewidth correlated photon pair light source generation system based on cavity-enhanced spontaneous parametric down-conversion

Abstract

The application discloses a narrow-line-width correlated photon pair light source generation system based on cavity-enhanced spontaneous parametric down-conversion, which comprises a pump coupling unit, a ring cavity resonance unit, an active frequency locking unit and a photon separation and detection unit, the pump coupling unit is used for emitting pump light, the ring cavity resonance unit comprises a knotted four-mirror ring cavity and a PPLN crystal, the PPLN is arranged between two flat-concave mirrors of the knotted four-mirror ring cavity, and the active frequency locking unit locks the cavity length of the knotted four-mirror ring cavity at the frequency of the pump light; the photon separation and detection unit comprises a dichroic mirror and a single-photon detector, the dichroic mirror is used for separating signal light and idler light, and low-noise coincidence counting measurement is carried out through the single-photon detector and a data acquisition card. The application realizes narrow-line-width output, single-longitudinal-mode output and higher spectral purity for the cesium atom D2 line; high brightness and narrow line width are considered, and long-term operation stability is better.