In this work, a thermally tunable dielectric metasurface (DMS) composed of InSb cylindrical micropillars is proposed to generate vortex beam in the terahertz region. The full ${2}\pi$ phase shift could be realized at resonance frequency for the incident linearly polarized wave by changing the diameter of InSb cylindrical micropillars. In addition, the resonance frequencies vary with the temperatures of the InSb cylindrical micropillars. More specifically, the resonance frequency will be moved from 0.69 to 1.65 THz when the temperature increases from 240 K to 340 K, and the corresponding transmission coefficients are higher than 0.5. Vortex beams carrying orbital angular momentums with different topological charges at 1.27 THz ($T = {300}\;{\rm K}$) and thermally tunable vortex beams with topological charge $m = - {2}$ can be achieved. The results showed that the generated vortex beams have high mode purity under different external environment temperatures. The vortex beam generator can reconstruct the operating frequency without changing the physical size, which has great potential in terahertz imaging, detecting, and communication.

中文翻译：

---

基于InSb超表面的热可调太赫兹涡旋光束发生器

在这项工作中，提出了一种由InSb圆柱微柱组成的热可调介电超表面（DMS），以在太赫兹区域产生涡旋光束。全$ {2} \ PI $相移可以在共振频率来实现，用于通过改变的InSb圆柱形微柱的直径线偏振波入射。此外，共振频率随InSb圆柱微柱的温度而变化。更具体地说，当温度从240 K增加到340 K时，谐振频率将从0.69 THz移到1.65 THz，并且相应的传输系数大于0.5。在1.27 THz处携带具有不同拓扑电荷的轨道角动量的涡旋光束（$ T = {300} \; {\ rm K} $）和具有拓扑电荷$ m =-{2} $的热可调涡旋光束可以实现。结果表明，所产生的涡旋光束在不同的外部环境温度下具有较高的模态纯度。涡旋光束发生器可以在不改变物理尺寸的情况下重建工作频率，这在太赫兹成像，检测和通信中具有巨大的潜力。