The Development Of The Laser Induced Fluorescence Detection Aerosol Device And Experiment Results

In recent years,biologic aerosol becomes increasing concern due to the global infectious diseases,smog pollution,air pollution and bioterrorism threat to the normal life of human beings Therefore,how to distinguish and realize real-time monitoring effectively and accurately is of great significance in aerosol monitoring researches.A laboratory equipment for detecting biologic aerosol based on laser induced fluorescence(LIF)principle is built and the fluorescence spectrum of riboflavin and NADH is elaborately studied respectively.The laser induced fluorescence lidar remote sensing scheme is also proposed,which provides a theoretical basis detecting biologic aerosol remotely.The main contents and work of this paper are as follows:1.A laboratory equipment is built based on the principle of laser-induced fluorescence and three typical fluorescent materials such as the riboflavin,NADH,rhodamine B is used to validate and evaluate the performance of the system.The fluorescence spectra of three fluorescent substances is acquired successfully.2.The factors of influencing the intensity of riboflavin and NADH fluorescence spectra using 355nm pulsed laser excitation is studied and identified.These factors include concentration,laser energy,solvent type,PH,and temperature.Researches on the relationship between these factors and the intensity of fluorescence spectrum is also carried out.The detection limit of this laboratory equipment is estimated.Finally,the fluorescence spectra of riboflavin aerosol is obtained as well as the relationship between aerosol particle size and fluorescence intensity.3.The overall design scheme of the laser induced fluorescence lidar is proposed,which including the selection of laser,telescope,photodetector,optical components and other major components.The influence of the laser single pulse intensity and the field of view of the telescope on the SNR is discussed.The effective farthest detection distance and the minimum detection concentration are simulated.Finally,the source of noise and the measures of noise reduction are analyzed.