Trace substance analysis device based on near-field optical traveling-wave absorption

Abstract

The invention relates to a trace substance analysis device based on near-field optical traveling-wave absorption. The prior art has a complex structure and high optical machine requirement, and fails to obtain high-precision spectral information. The device comprises an annular high-fineness cavity consisting of a single optical element, namely an isosceles triangular prism, and two equicrural surfaces are high-reflectivity surfaces; a light beam is incident from one high-reflectivity equicrural surface, performs the total internal reflection on the bottom surface of the prism to form a near-field optical test area, forms optical traveling-wave in the isosceles triangular prism, and emerges from another high-reflectivity equicrural surface; the emergent light beam passes through a high-precision light splitting unit of an Fabry-Perot cavity consisting of two high reflection mirrors, and a moving part drives one high reflection mirror of the Fabry-Perot cavity to move along the axial direction to adjust and control emergent spectral information; and a photoelectric detector receives an emergent beam from the Fabry-Perot cavity, forms a high-precision spectrum signal, and realizes the detection of trace substances. The device has the characteristics of simple and steady system structure, high precision of spectral information, less quantity of needed detected substances, broad applicable range and the like.

Description

technical field [0001] The invention belongs to the field of optical technology, and relates to a spectroscopic analysis device, in particular to a trace substance analysis device based on near-field optical traveling wave absorption, which is mainly used for the analysis of fluids, films, tiny particles, biomolecules, residual pesticides and other substances Trace concentration test. technical background [0002] In many fields such as advanced manufacturing industry, environmental analysis, life science, medical treatment, national defense and security, there are a large number of trace measurement requirements for substances, and the requirements for detection sensitivity of trace substances are getting higher and higher. High-precision cavity absorption spectroscopy has become one of the development trends of trace substance measurement technology due to its advantages of high detection sensitivity, absolute measurement, and good selectivity. High-precision cavity spect...

AI Technical Summary

Problems solved by technology

The high-definition cavity spectral analysis system has considerable advantages, but there are still some shortcomings: 1) the linear fine-scale cavity structure is adopted, and the laser forms an optical standing wave in the high-definition cavity, resulting in uneven distribution of light intensity, and The reflected light of the cavity mirror at the incident end of the beam is likely to interfere with the laser; 2) It can only be used to test and analyze fluid substances, and cannot test the trace concentration of thin films, interfaces, nano-materials and other morphological substances. When measuring fluids, it needs to be The detection fluid has a certain volume, and it is impossible to detect a small amount of the measured fluid; 3) when the laser beam enters and exits the sample cell, in order to prevent the loss of light energy at the interface, it must be incident and exited at the Brewster angle, so that The requirements for the mechanical positioning of the sample cell and the control accuracy of the beam direction are increased; 4) The high-precision cavity in the cavity ring-down spectroscopy analysis system is composed of two or more high-reflectivity mirror optical elements, and the structure is complex; 5) After the beam emerges from the high-definition cavity, it is received by the photoelectric sensor without high-precision light splitting, and high-precision spectral information of the outgoing light cannot be obtained. The accuracy of the spectral information is not high, which affects the detection accuracy and material discrimination ability

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