Method for improving diamond NV color-center photon producing and collecting efficiency

Abstract

The invention discloses a method for improving diamond NV color-center photon producing and collecting efficiency. The exciting effect of a 532 nm light field on a diamond NV color center is achieved by the aid of local effect of hollow optical fiber, and photons emitted by the NV color center are trapped in the optical fiber and are transmitted along the optical fiber; a transmitter lens is added to the other end of the optical fiber to feed back 532nm laser to the optical fiber, and the photons generated by the diamond NV color center are fed back to the optical fiber. The photons emitted by the diamond color center in the optical fiber are collected forward and backward, and the collecting efficiency can approximate to 100%; high photon collecting efficiency is achieved; due to existence of the local efficiency of the optical fiber and a feedback mechanism, the NV color center is excited only by weaker 532nm laser, and higher photon producing efficiency can be achieved; simpleness in structure is achieved, operation is convenient, and application prospect is wider.

Description

technical field [0001] The invention relates to a method for improving the generation and collection efficiency of diamond NV color center photons. The method has a collection efficiency of almost 100%, and also has the advantages of stable output, simple and compact structure, easy integration and the like. Background technique [0002] NV color center is a kind of light-emitting point defect in diamond crystal. A nitrogen atom replaces a carbon atom in diamond, and there is a hole in the adjacent position. Such a point defect is called NV color center. The diamond NV color center is a very important physical system, especially for a wide range of applications in the fields of quantum technology (including quantum metrology, quantum information process, quantum communication, etc.) and biological imaging. Considering the application prospects of diamond NV color centers in these aspects, the research on it has always been a hot issue in physics research. But usually, only ...

AI Technical Summary

Problems solved by technology

However, only a small part of the photons emitted by the NV color centers inside the block diamond can be refracted on the diamond surface and collected by the objective lens. Collection efficiency ≤ 10% (using an objective lens with a maximum numerical aperture of 1.49), while considering the coupling and quantum efficiency of the detector, the detection efficiency of photons is < 2%

The low photon collection efficiency severely limits the application of diamond NV color centers in the fields of quantum information and quantum physics

[0003] In order to improve the collection efficiency of photons, the traditional method is to etch the shape of the lens on the surface of the block diamond by means of ion beam etching, or use modern micro-nano technology to produce some special micro-nano structures, etc., but these methods The implementation device is very complicated, and the requirements for the experiment are very high

Recently, some research groups have reported using side-collection technique to improve photon collection efficiency. This scheme uses four photodetectors to collect photons emitted by the NV color center from around the diamond sample, and the collection efficiency reaches 47%, but the collection efficiency of this method is still low, there is still a large room for improvement, and in order to improve the photon collection efficiency, four photodetectors need to be used

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