【摘要】 氟化镁材料在太赫兹波段是一种天然双曲材料,在双曲特性波段理论上可以支持波矢非常大的电磁模式,因此利用能量较低的自由电子可以在氟化镁中激励起太赫兹波段的切伦科夫辐射。本文利用数值模拟方法仿真了自由电子在氟化镁中的切伦科夫辐射,结果表明能量为0.1～20 keV的自由电子可以在氟化镁中产生频率区间7.4～9 THz和12～13.3 THz的切伦科夫辐射,并且仿真得到的模式等效折射率、辐射波长和辐射角等结果与理论公式获得的结果吻合较好。本文的研究工作为进一步实验探索氟化镁中的切伦科夫辐射的可行性奠定了基础,为产生太赫兹辐射提供了新的思路。更多还原

【Abstract】 Magnesium fluoride（MgF₂） is a kind of natural hyperbolic material in terahertz wave region. It can support electromagnetic modes with very large wave vector theoretically in the hyperbolic frequency bands. Thus terahertz Cherenkov Radiation（CR） can be derived in MgF₂ by utilizing low energy free electrons. In this paper, CR generated by free electron in MgF₂ is simulated using particle-in-cell finite-difference time-domain method. The simulation results indicate that CR in the frequency bands of 7.4～9 THz and 12～13.3 THz could be obtained when electron energy is between 0.1～20 keV, and the effective index, radiation wavelength and radiation angle are in good agreement with the theoretical ones. This work establishes?the foundation for further experimental study on CR in MgF₂ and also provides a new approach for terahertz wave emitting.更多还原