双色拉盖尔—高斯涡旋激光诱导气体产生太赫兹波

Terahertz Generation by Two-Color Laguerre-Gaussian Vortex Laser

  • 摘要: 太赫兹(THz)辐射具有非电离性、强穿透性和丰富的指纹谱信息,在成像探测、宽带通信和物质调控等领域具有重要应用价值。近年来,携带轨道角动量的涡旋太赫兹光束因其中心暗核、环形强度分布和螺旋相位的结构,在结构化光场研究中受到广泛关注。强激光场驱动气体等离子体是一种有效的宽带太赫兹产生方式,当驱动激光采用涡旋光束时,其角向相位信息可通过电离和瞬态光电流过程传递至太赫兹辐射场。本文基于光电流模型,研究了双色拉盖尔—高斯涡旋场与气体等离子体相互作用产生THz辐射的规律,结果表明,THz辐射模式由驱动激光的频率比、拓扑荷数等参数共同决定。通过合理选择这些参数,可以实现太赫兹空心高斯光束与太赫兹涡旋光束的有效调控。本研究为结构化THz辐射的可控产生提供了理论依据。

     

    Abstract: Terahertz (THz) radiation, with its non-ionizing property, strong penetrating power and rich fingerprint spectral information, has significant application value in fields such as imaging detection, broadband communication and material regulation. In recent years, vortex terahertz beams carrying orbital angular momentum have received extensive attention in structured light field research due to their central dark nucleus, annular intensity distribution and helical phase structure. Strong laser field-driven gas plasma is an effective way to generate broadband terahertz. When the driving laser uses a vortex beam, its angular phase information can be transferred to the terahertz radiation field through ionization and transient photocurrent processes. Based on the photocurrent model, this paper studies the law of THz radiation generated by the interaction between the bicolor Laguerre-Gaussian vortex field and gas plasma. The results show that the THz radiation mode is jointly determined by parameters such as the frequency ratio of the driving laser and the topological charge number. By rationally selecting these parameters, effective control of terahertz hollow Gaussian beams and terahertz vortex beams can be achieved. This study provides a theoretical basis for the controllable generation of structured THz radiation.

     

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