【摘要】 在室温条件下,基于太赫兹时域频谱(THz-TDS)技术研究了SBN:Ce陶瓷在532 nm连续激光激发下的介电响应.在外加光场的作用下,该陶瓷的介电常数表现出良好的调制特性,介电改变量达到8.5%;同时,介电损耗增加了15%.实验结果表明,该材料折射率的变化|Δn|与外加光场强度呈现线性关系.通过建立模型,分析了SBN:Ce陶瓷的光-铁电机理,这些实验结果可以被归结为,激发的自由载流子在样品内部形成的内建电场导致的介电常数改变.探索铁电陶瓷材料在太赫兹波段的光-铁电性质对于太赫兹波调制器件的研究具有指导意义.更多还原

【Abstract】 The dielectric response of SBN: Ce ceramics to the 532 nm cw laser w as investigated at room temperature by means of a terahertz time-domain spectroscopy. When the external laser field is imposed onto the SBN: Ce ceramics,the permittivity of the sample show s an appreciable change w ith amplitude variation up to 8. 5% and the dielectric loss increase 15%,respectively. The refractive index | Δn | varies linearly w ith the intensity of the applied laser. The photoferroelectric physical mechanisms of SBN: Ce ceramics can be attributed to the internal space field in the ceramics caused by the light excited free carries w ith the analytic models. The results present important references for design and selection of the terahertz tunable devices.更多还原