提出了一种基于激光差分探测技术的悬浮物质量浓度测量方法,用于测量烟雾、粉尘等空气悬浮颗粒的含量。利用悬浮颗粒对光的散射,可以在不影响悬浮物颗粒特性的前提下,对其实现实时在线监测。另外，借助于参考光与测试光的直接差分放大,可以消除激光能量起伏以及其他扰动对测量的干扰。通过对激光在悬浮物颗粒中传播时衰减原理的研究,获取悬浮物颗粒质量浓度与光强衰减的关系,搭建了一套激光差分探测悬浮物质量浓度的实验系统,进行烟雾质量浓度的实际测量,验证了该测量方法的可行性。

A method based on laser difference detection for measuring suspended matter concentration is introduced in the paper. It can be used for the concentration measurement of suspended particles such as smog, dust and other aerosols. Based on the light scattering effect of the suspended particles, real-time monitoring of the suspended particles without changing their properties can be achieved. By means of a direct amplification of the differential signal of the test and reference light, fluctuations of the laser energy can be reduced. The measuring principles and methods are presented in detail. Through the study of the light decaying mechanism during laser propagating in the suspended particles, the relationship between the suspended matter concentration and light intensity attenuation is deduced. We also build a laser differential detection system for the measurement of the suspended matter concentration. By measuring the smog of known concentration, practical feasibility of the measurement method is verified.