Abstract-Frequency spectrum characterization of terahertz emission from laser-induced air plasma

Ji Zhao   Liangliang Zhang   Yiman Luo   Tong Wu   Cunlin Zhang   Yuejin Zhao 

http://www.opticsjournal.net/abstract.htm?id=OJ140723000036cIfLhO

Terahertz (THz) emission from laser-induced air-plasma is presented. The frequency spectra of THz wave are investigated using an air-biased-coherent-detection method. The frequency spectra are measured under different pump-pulse and probe-pulse energies. The frequency spectra become narrow with the increasing pump power and we speculate it caused by collision behavior. Meanwhile, the bandwidth of the frequency spectra is broadened by the increasing probe power, which can be explained by pulse compression. Based on this finding, the optimal frequency spectrum of THz can be achieved by regulating the probe and pump beam.