Controllable terahertz radiation from a linear-dipole-array formed by a two-color laser filament in air

Zhang, Zhelin and Chen, Yanping and Chen, Min and Zhanag, Zhen and Yu, Jin and Sheng, Zheng-Ming and Zhang, Jie (2016) Controllable terahertz radiation from a linear-dipole-array formed by a two-color laser filament in air. Physical Review Letters, 117 (24). ISSN 0031-9007

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    Abstract

    We have demonstrated the effective control on carrier-envelope phase, angular distribution as well as peak intensity of a nearly single-cycle terahertz pulse emitted from a laser filament formed by two-color, the fundamental and the corresponding second harmonics, femtosecond laser pulses propagating in air. Experimentally, such control has been performed by varying the filament length and the initial phase difference between the two-color laser components. A linear-dipole-array model, including the descriptions of the both generation (via laser field ionization) and propagation of the emitted terahertz pulse, is proposed to present a quantitative interpretation of the observations. Our results contribute to the understanding of terahertz generation in a femtosecond laser filament and suggest a practical way to control the electric field of terahertz pulse for potential applications.