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| 飞秒激光泵浦光电导天线太赫兹辐射源波束特性研究 |
| Research on terahertz radiation beam performance based on femtosecond laser-pumped photoconductive antenna |
| 投稿时间:2024-03-08 |
| DOI:10.3969/j.issn.1005-5630.202403080043 |
| 中文关键词: 太赫兹 光导天线 硅透镜 肖特基检波器 CST仿真 方向性 |
| 英文关键词:terahertz photoconductive antenna silicon lens Schottky detector CST simulation directivity |
| 基金项目:国家自然科学基金(61731020) |
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| 中文摘要: |
| 飞秒激光泵浦光电导天线发射太赫兹波是目前使用最广泛的宽频太赫兹产生技术。为提高发射效率和波束质量,通常在光电导天线发射端面集成硅透镜,以增强辐射效率和方向性。然而,由于装配误差或实验调节不当,泵浦飞秒激光光斑中心(太赫兹辐射中心)可能偏离硅透镜旋转对称轴,导致太赫兹波辐射方向发生偏移、波束质量劣化以及发射效率降低。实验采用GaAs肖特基二极管检波器对光电导天线辐射波束进行机械扫描成像,系统研究了太赫兹辐射中心偏离硅透镜对称轴对辐射方向的影响。研究发现,太赫兹辐射中心偏离透镜会导致太赫兹波束向相反方向偏转,这为实际应用中光电导天线辐射发生偏移时透镜位置的调整提供了依据。通过CST电磁仿真,模拟了太赫兹辐射中心相对于透镜旋转对称轴的偏移情况,仿真结果与实验一致。 |
| 英文摘要: |
| Terahertz (THz) radiation generated by femtosecond laser-pumped photoconductive antenna (PCA) is the most widely used THz wide-frequency source at present. A hemispherical or super-hemispherical silicon lens is usually integrated with a PCA to improve its radiation directivity, beam quality, and radiation efficiency. However, due to the misalignments of the laser focused spot, and between the PCA and the silicon lens, the THz radiation center is not on the rotation symmetrical axis of the silicon lens, resulting in the deviation of THz radiation direction, the deterioration of THz beam quality, and the reduction of radiation efficiency. In this work, a GaAs Schottky detector, mounted on a two-dimensional translation stage was used to obtain the spatial profile of a THz beam radiated from a PCA integrated with a silicon lens. The influence of misalignment between the PCA and the silicon lens on the radiation directivity was clarified. The problem of how to adjust the position of the lens when the radiation of the PCA is offset in the experiment is solved. The effects of misalignment between the PCA and the silicon lens are numerically simulated by using the CST electromagnetic simulation package. The simulation results are consistent with the experiment data. |
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