An ultrasensitive gas sensor based on graphene D-shaped optical fiber

Abstract

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. The present invention adjusts the graphene Fermi energy level by applying an external voltage through the gold-graphene-gold heterojunction structure. By applying an external voltage, the graphene Fermi energy level is adjusted to a position close to the Dirac point. When the sensed gas molecules are adsorbed onto the graphene, the carrier concentration of the graphene changes, causing a small change in the Fermi level. Since the Fermi energy level of graphene is close to the Dirac point at this time, the four-wave mixing signal excited by the input pump light of the graphene D-shaped fiber is most sensitive to the response of the external sensing molecules. At this time, the sensing sensitivity reaches optimal. The invention significantly enhances the interaction between the input optical signal and external sensing molecules, has small volume, simple structure, and the sensing sensitivity reaches the single molecular weight level. It adopts an all-fiber structure and can be easily connected to the optical fiber sensing and communication network to realize Fast real-time monitoring.

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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