Super-sensitive gas sensor based on graphene D-shaped optical fiber

Abstract

The invention belongs to the field of sensing, and particularly relates to a super-sensitive gas sensor based on a graphene D-shaped optical fiber. According to the invention, external voltage is applied through a gold-graphene-gold heterojunction structure to adjust the Fermi level of graphene; by applying external voltage, the Fermi level of the graphene is adjusted to a position close to a Dirac point, and when sensed gas molecules are adsorbed to the graphene, the carrier concentration of the graphene is changed, so that tiny change of the Fermi level is caused. As the Fermi level of the graphene is close to a Dirac point, a four-wave mixing signal of the graphene D-shaped optical fiber excited by input pump light is most sensitive to response of external sensing molecules, and the sensing sensitivity is optimal at the moment. According to the invention, the interaction between an input optical signal and an external sensing molecule is remarkably enhanced, the size is small, the structure is simple, the sensing sensitivity reaches a single molecule level, an all-fiber structure is adopted, the optical fiber sensing and communication network can be conveniently accessed, and rapid real-time monitoring is realized.

Description

technical field [0001] The invention belongs to the field of sensing, and in particular relates to an ultrasensitive gas sensor based on a graphene D-shaped optical fiber. Background technique [0002] With the continuous development of industry and the continuous improvement of people's living standards, gas sensors have been widely used in people's daily life to detect flammable, explosive, toxic and harmful gases, and to monitor the concentration of gas raw materials or products in industrial synthesis, and the composition of waste gas. and detection of air pollution. [0003] There are many types of gas sensors, which can be divided into electrical, optical, electrochemical and others according to their working principles. Semiconductor sensors and electrochemical sensors are the most common. Semiconductor sensors are low in cost, mature in technology, high in sensitivity, long in life, and low in sensitivity to humidity, but their performance is closely related to the...

AI Technical Summary

Problems solved by technology

However, they are simply attaching the thin film material to the corresponding polishing plane, and the sensing sensitivity is mainly determined by the material itself.

Once the thin film material is attached to the polished area of ​​the D-shaped fiber, the sensing sensitivity of the corresponding device has been determined, which also limits the sensitivity of traditional D-shaped fiber-based sensors.

In recent years, the research on sensors based on D-shaped optical fiber is mainly to expand the application of sensors based on D-shaped optical fiber by changing the thin film material attached to the D-shaped optical fiber, and the innovative research on its sensitivity is mainly by changing the same material. The nature of the material to improve the sensitivity of a specific type of sensor does not actually improve the sensitivity of the D-shaped fiber sensor, which is also the limitation of the sensor based on the D-shaped fiber

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