Humidity sensor based on terahertz plasma enhancement effect and system thereof

Abstract

The invention provides a humidity sensor which is characterized by comprising a machine frame, a mobile unit, a weighing bench, an optical grating and a prism unit, wherein the mobile unit is arrangedon the machine frame and comprises a micrometer caliper and a scale plate, the weighing bench is arranged on the mobile unit and can be driven by the mobile unit to move up and down, the optical grating is arranged on the weighing bench, the prism unit comprises a clamping assembly arranged on the machine frame and a prism clamped by the clamping assembly, the prism unit is used for receiving terahertz optical and being coupled with the optical grating to generate a resonance peak, and a refractive index of the prism is larger than that of air. According to the humidity sensor disclosed by the invention, the situation that an absorption peak of vapor in a terahertz wave band right coincides with a resonance peak of a surface plasmon polariton generated by the optical grating under the terahertz attenuation total reflection action is utilized, so that a moisture content in air can be quickly measured in real time, flexibility is greatly improved, and a resolution ratio is higher. In addition, the humidity sensor has the advantages of simple structure, wide material taking and easiness in processing.

Description

technical field [0001] The invention relates to a humidity sensor, in particular to a humidity sensor based on a terahertz plasma enhancement effect and a system thereof. Background technique [0002] The high-sensitivity humidity sensor with terahertz plasma enhancement effect mainly uses the principle of prism coupling. Although the research on prism coupling sensor is very mature in the optical band, it develops slowly in the terahertz band because it cannot be used on smooth metal in the terahertz band. The surface efficiently excites surface plasmon polaritons. Prism-coupled terahertz sensors were not gradually developed until British scientist J.B.Pendry etched periodic structures on smooth metal surfaces to effectively excite surface plasmon polaritons in the terahertz band. Among them, there are generally two models of prism-coupled sensors: Otto model and Kretschmann model. Prism structures have previously been used to excite surface modes in metals and semiconduc...

AI Technical Summary

Problems solved by technology

The traditional capacitive relative humidity sensor works in contact with the gas in the measured environment. Once the gas in the measurement environment contains substances that are "incompatible and intolerable" with the capacitive sensor, it will affect the sensor's working performance.

In particular, some special substances are even corrosive and damage the sensor. In addition, the service life of electronic products is relatively short, the circuit is easy to be disturbed and degraded by the outside world, the sensitivity is not high enough, and the real-time performance is poor.

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