利用光泵浦太赫兹探测系统研究了3个基于开口谐振环的超材料的光调制性质。结果表明: 当太赫兹波的电场矢量平行于超材料底边, 设计太赫兹超材料时, 需要避免对称性样品的中间条等长。然而, 非对称性的样品存在耦合和劈裂现象。由于不同的共振机制, 低频LC共振对光较为敏感。虽然样品由于设计结构的区别使得各自共振峰位有所不同, 但它们对光所呈现出的调制特性是相同的。即当太赫兹波的电场矢量平行于超材料两侧的边时, 由于结构的原因在透射谱中只有一个透射凹陷, 此透射凹陷表现为偶极共振且该偶极共振特性对光激励不敏感。

By utilizing optical pump terahertz probe spectroscopy, the optical modulated properties of three samples were investigated with terahertz subwavelength structures, which were derived from classical split ring resonators. The obtained results show in the metamaterials design, it is needed to avoid the same length bar in the middle of the symmetric samples due to the fact that the middle bar has less influence on the resonant property when the terahertz electric field vector is parallel to the bottom bar. However, the asymmetric samples exist coupling and splitting phenomenon in transmission spectra. For the different resonance mechanisms, it is found the LC resonance has higher sensitivity than the dipole resonance to the pump excitation. Although different designed structures will exhibit different resonant positions in frequency, the optical modulation behaviors of those samples have one same characterization. That is, when the terahertz electric field vector is parallel to the bilateral bar, there is only one transmission dip because of the structure design and this transmission dip from the dipole resonance is not sensitive to the pump excitation.