Modeling of spectral emission-based lidar remote sensing

Abstract

Stand-off Laser-Induced-Thermal-Emission (LITE), Laser-Induced-Breakdown Spectroscopy (LIBS), and remote Raman Lidar are being studied for the remote sensing of a wide range of target substances, including explosive and chemical species. Each of these techniques use a transmitted laser beam to remotely excite a spectral emission process at a distant target, have some optical and detection characteristics in common, but also have several other excitation and delivery aspects that are unique to each technique. In order to better understand these techniques, we are developing a computer program to model and simulate a LITE, LIBS, and Raman lidar system for the stand-off detection and spectral identification of close to moderate range target species. In particular, a modified lidar equation has been used for the LIBS technique, in which the influence of the transmission of the atmosphere is also computed to determine its influence on the backscattered spectral information as a function of wavelength and range. The standard Lidar equation was modified to take into account the emission of a laser induced source at a range r, and the subsequent transmission of the emission back toward the (Lidar) telescope receiver. Applications for LITE and Raman lidar analysis are planned.