title: Theoretical research on terahertz air-breakdown coherent detection with the transient photocurrent model.
abstract: The physical mechanism for sensing broadband terahertz (THz) wave via using femtosecond (fs) laser induced gas plasma without any local accessory near the plasma, i.e. THz air breakdown coherent detection, is systemically investigated by utilizing the transient photocurrent model. Previous observed results, such as conversion from incoherent to coherent detection, can be numerically obtained. Further calculations and analysis show that it is through modification of the gas ionization process, and not acceleration of freed electrons or through a four-wave-mixing (FWM) process, that the THz waveforms can be encoded into the detected second harmonic (SH) signals.
authors.affiliation: Wuhan National Laboratory for Optoelectronics, School of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Hu
authors.initials: H
authors.lastname: Wang
authors.forename: Kejia
authors.initials: K
authors.lastname: Wang
authors.forename: Jinsong
authors.initials: J
authors.lastname: Liu
authors.forename: Houmei
authors.initials: H
authors.lastname: Dai
authors.forename: Zhengang
authors.initials: Z
authors.lastname: Yang
mesh_terms: D003198:Computer Simulation; D008027:Light; D008956:Models, Chemical; D058626:Plasma Gases / Q000737:chemistry* / Q000528:radiation effects*; D055053:Terahertz Radiation
chemical_list: D058626:Plasma Gases