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

Abstract

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.

Description

technical field [0001] The invention relates to a two-dimensional magneto-optical trap system, in particular to a two-dimensional magneto-optical trap system and a method for preparing a narrow linewidth single photon source, belonging to the technical field of photon transmission. Background technique [0002] Photon is the basic particle that transmits electromagnetic interaction, and is the carrier of electromagnetic radiation. In quantum field theory, photon is the mediator that transmits electromagnetic interaction. In quantum communication system, it is considered as an ideal information transmission carrier, but the channel The photon decays exponentially with the transmission distance, which limits the communication distance. Long-distance quantum communication requires the use of quantum relay based on quantum memory, and the photon linewidth that can be stored in quantum memory cannot be greater than the natural linewidth (MHz order). , so narrow-linewidth single-p...

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Problems solved by technology

[0002] Photon is the basic particle that transmits electromagnetic interaction, and is the carrier of electromagnetic radiation. In quantum field theory, photon is the mediator that transmits electromagnetic interaction. In quantum communication system, it is considered as an ideal information transmission carrier, but the channel The photon decays exponentially with the transmission distance, which limits the communication distance. Long-distance quantum communication requires the use of quantum relay based on quantum memory, and the photon linewidth that can be stored in quantum memory cannot be greater than the natural linewidth (MHz order). , so a narrow linewidth single photon source is crucial

[0003] At present, the cavity-enhanced spontaneous parametric down-conversion process is generally used to generate narrow-linewidth entangled photon pairs, and then a common method to obtain a narrow-linewidth single-photon source. However, the defect of this method is that the control of the optical cavity is technically relatively It is difficult, and the central frequency of photons generated at the same time is also difficult to meet the requirements of quantum memory

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