Surface microstructure silicon cantilever enhancement type optical-thermal spectrum trace gas detection method and device

Abstract

The invention relates to a surface microstructure silicon cantilever enhancement type optical-thermal spectrum trace gas detection method and device. The device comprises a tunable laser, a reflective object, a surface microstructure silicon cantilever, a concave mirror, an optical fiber, an optical fiber coupler, a continuous laser, a laser controller, an optical detector, a signal processing system and the like. Modulated light emitted from the tunable laser is reflected on the concave mirror by the reflective object after passing through the gas to be detected, the received reflective light on the concave mirror is focused on a silicon surface of the cantilever beam. After the optical energy is absorbed by the cantilever beam, the optical-thermal deflection occurs to generate resonance. If the gas concentration is higher, the optical intensity absorbed by the gas is larger, and if the optical energy absorbed by the cantilever beam is smaller and the resonance amplitude is smaller. A length adjustable Fabry-Perot cavity is formed by an optical fiber end surface and a metal surface of the cantilever beam, the amplitude of the cantilever beam is demodulated to obtain gas absorption spectrum, furthermore the concentration of the detected trace gas is obtained. The device has the advantages of cheap price, small size, simple structure, convenience in use, strong flexibility, high detection sensitivity, and field work capacity and can be widely used in remotely detecting the components and concentration of a variety of or multi-component trace gas.

Description

technical field [0001] The invention relates to gas detection technology, especially a photothermal spectrum trace gas detection method and device for remote detection of trace gas based on a surface microstructure silicon cantilever beam working in an open environment, which can be widely used in remote It is widely used in fields such as explosive detection, environmental monitoring, and detection of toxic and hazardous gases. Background technique [0002] The development of trace gas long-distance detection technology is of great significance for atmospheric environment monitoring, long-distance detection of explosives and detection of biological and physiological states. Absorption spectroscopy gas detection technology has the advantages of large measurement range, multi-component measurement, continuous monitoring, etc., and has gradually become an ideal trace gas concentration detection tool. Absorption spectroscopy gas detection technologies mainly include differenti...

AI Technical Summary

Problems solved by technology

However, due to the very low absorption efficiency of the silicon nitride cantilever beam for incident light, its ability to detect weak light signals is greatly reduced, making it impossible to perform long-distance spectral detection; moreover, the cantilever beam has low flexibility and low thermal deflection efficiency , so it is necessary to use an expensive high-precision position-sensitive detection system to pick up the vibration amplitude of the cantilever beam, resulting in a complex system structure and high prices

Images