Abstract-Dual-frequency terahertz emission from splitting filaments induced by lens tilting in air

Zhelin Zhang¹, Yanping Chen^1,a), Liu Yang¹, Xiaohui Yuan¹, Feng Liu¹, Min Chen¹, Jianqiu Xu¹, Zhengming Sheng^1,2 and Jie Zhang¹
http://scitation.aip.org/content/aip/journal/apl/105/10/10.1063/1.4895720
1 Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
2 Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
a) Author to whom correspondence should be addressed. Electronic mail: yanping.chen@sjtu.edu.cn
Appl. Phys. Lett. 105, 101110 (2014); http://dx.doi.org/10.1063/1.4895720

Dual-frequency terahertz radiation from air-plasma filaments produced with two-color lasers in air has been demonstrated experimentally. When a focusing lens is tilted for a few degrees, it is shown that the laser filament evolves from a single one to two sub-filaments. Two independent terahertz sources emitted from the sub-filaments with different frequencies and polarizations are identified, where the frequency of terahertz waves from the trailing sub-filament is higher than that from the leading sub-filament.