Two-dimensional magnetic optical trap system and narrow line width single photon source preparing method thereof

The invention discloses a two-dimensional magnetic optical trap system and a narrow line width single photon source preparing method thereof. The system comprises two pairs of reversed Helmholtz coils, a quartz vacuum cavity, an ion pump, a current feed through part with alkali metal releasing agent, a vacuum valve, a six-way connector, a first glass window, a second glass window and a first semiconductor laser. Six openings of the six-way connector are respectively connected with the quartz vacuum cavity, the ion pump, the current feed through part, the vacuum valve, the first glass window and the second glass window. The two pairs of reversed Helmholtz coils are respectively arranged in a horizontal-symmetrical mode and in a vertical-symmetrical mode. According to the method, the two-dimensional magnetic optical trap system obtains a long-strip-shaped cold atomic group through cooling light, then spontaneous radiation four-wave mixing is used, Stokes photons and reversed Stokes photons are generated through pump light and coupling light, and the photons are collected. The line width of a narrow line width single photon source prepared by the two-dimensional magnetic optical trap system is in the megahertz magnitude, and the narrow line width single photon source is suitable for long-distance quantum communication.