Teramobile: Study of long-distance propagation of fs-TW laser pulses in air, and atmospheric applications: Lidar remote sensing, lightning control

• Applicant: Professor Dr. Roland Sauerbrey
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 1999 to 2006
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5190496

Lidar (Light Detection and Ranging) provides a three-dimensional and time-resolved analysis of compositon of the atmosphere. These data are essential in order to understand the dynamics of pollution and to validate numerical models of the global climate or those used to forecast urban pollution peaks. However, the applications of present Lidar technology are limited by following points: lidars are based on Rayleigh and Mie backscattering which scatter laser pulses almost isotropically. Hence, Lidar signals decrease strongly with the detecting solid angle, which limits the measuring range. The number of gaseous pollutants that can be detected by Lidar is limited by the present ability to generate high energy laser pulses with broad tunability, especially in the infrared. Today, only compounds strongly absorbing in the UV, such as NO₂, SO₂, or O₃, may be detected. Moreover, only one pollutant can be measured at one time. Aerosol characterisation by present Lidars is limited to their concentration, and in the best cases, to their size distribation. Other information, such as their composition, size or charge, remain out of reach to Lidar. The purpose of the French-German "Teramobile" project is to provide solutions to these important limitations, by using non-linear optics in the atmosphere, especially white light filaments. This project is based on the construction of a femtosecond laser system with terawatt peak power, integrated in a mobile unit. This mobile femtosecond terawatt laser will then be used to study the transmission of ultrafast and high-peak-power pulscs in the atmosphere and to organise measurements campaigns on various sites such as urban and industrial areas,.... Besides Lidar, a mobile terawatt laser system will be usefull in many atmospheric applications. Due to the generation of a plasma channel during its propagation, it may suitable for laser-induced cloud condensation, as well as storm protection of sensible installations such as power plants. In this application, the plasma channel plays the role of a virtual lightning conductor. The Teramobile system will also be used for more fundamental research in the field of light-matter interaction. We will use the mobility of the system to perform short test experiments at large facilities such as synchrotrons, where it would not be possible to implement a static femtosecond laser for a few weeks´ experiment.

• DFG Programme: Research Grants
• International Connection: France
• Participating Persons: Dr. Jerome Kasparian; Professor Dr. André Mysyrowicz; Professor Dr. Jean-Pierre Wolf; Professor Dr. Ludger H. Wöste