Raman gas analyzing device of column vector field excited hollow core photonic crystal fiber

Abstract

The invention relates to a Raman gas analyzing device of column vector field excited hollow core photonic crystal fiber. The prior art has defects of complex structure, low sensitivity and high structural requirement. According to the invention, the surface-enhanced Raman effect and the hollow core photonic crystal fiber technology are combined, and the device is based on the gas Raman analysis principle. A detected gas flows through hollow cavity of hollow core photonic crystal fiber, and a surface-enhanced Raman structural layer is arranged at the inner side of the hollow cavity of the hollow core photonic crystal fiber; by a column vector filed, one end of the fiber is coupled into the hollow core photonic crystal to realize Raman excitation, a photoelectric detection part detects a Raman scattering signal, and analysis is carried out to obtain matter character information of the detected gas. The device provided by the invention has characteristics of low dosage of the detected gas, high sensitivity, high signal to noise ratio, strong resistance to interference, low positioning requirement, easily constructed system, easy miniaturization, strong analysis and discrimination capability, wide application range, easily expanded function and the like.

Description

technical field [0001] The invention belongs to the field of optical technology, and relates to a gas analysis device, in particular to a Raman gas analysis device for exciting a hollow photonic crystal fiber by a column vector light field. Background technique [0002] Gas analysis and detection are widely used in environmental monitoring, medical diagnosis, process control, food safety, quality inspection, biological research, life sciences, national defense security, quarantine inspection and other fields, and the requirements for gas analysis and detection in these fields are getting higher and higher. In the prior art, there is a high-precision cavity-enhanced spectroscopic analysis system, see US Patent "Cavity ring down arrangement for non-cavity filing samples", patent number: US6,452,680B1. The system has certain advantages, but there are some essential deficiencies: 1) The system adopts a linear high-definition cavity structure, and the laser forms an optical stand...

AI Technical Summary

Problems solved by technology

The system has certain advantages, but there are some essential deficiencies: 1) The system adopts a linear high-definition cavity structure, and the laser forms an optical standing wave in the high-definition cavity, and the light intensity distribution is uneven; 2) The beam incident end cavity mirror 3) When the laser beam enters and exits the sample cell, it must enter and exit at the Brewster angle, which increases the mechanical positioning requirements of the sample cell and the control accuracy of the beam direction 4) The high-precision cavity is composed of two or more high-reflectivity mirror optical elements, the structure is complex, and it is difficult to realize miniaturization; 5) Therefore, the principle of spectral analysis used limits its gas Substance Analysis Discrimination Ability

In the prior art, there is also a cavity-enhanced trace gas detection device based on the Raman effect, see the laser gas analyzer product of AtmosphereRecovery in the United States. This laser gas analyzer has certain advantages, but there are also some shortcomings: 1) The linear fineness cavity structure is also used, resulting in uneven distribution of light intensity, and the reflected light from the cavity mirror at the incident end of the beam is likely to interfere with the laser; 2) Due to the active cavity structure, the laser working medium and the gas chamber are both Inside the resonant cavity, this increases the complexity of the system, reduces the anti-interference performance of the device, and affects the adaptability of the device to field use; 3) The system has high performance requirements for key components such as laser cavity, optical filter, and sensor; 4) Structural positioning requirements High, difficult to miniaturize

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