氧化镁单晶在太赫兹波段的介电特性  

Terahertz dielectric properties of single-crystal MgO

作　　者：任冠华[1] 赵红卫[2] 张建兵[2] 田震[1] 谷建强[1] 欧阳春梅[1] 韩家广[1] 张伟力[1] 

机构地区：[1]天津大学精密仪器与光电子工程学院光电信息技术科学教育部重点实验室太赫兹波研究中心,天津300072 [2]中国科学院上海应用物理研究所,上海201800

出　　处：《红外与激光工程》2017年第8期6-10,共5页Infrared and Laser Engineering

基　　金：国家重点基础研究发展计划(2014CB339800);国家自然科学基金(61427814;61138001;61422509)

摘　　要：利用太赫兹时域光谱系统,在0.5~9.5 THz范围内对氧化镁单晶基片的介电特性进行了研究,并获得折射率、吸收系数以及复介电函数信息。实验数据表明,在低频(<2 THz)范围内,氧化镁单晶透过性较好,折射率在3.12~3.15之间。折射率和吸收系数均随频率增加而增大,且在3.16 THz和8.11 THz两处存在明显的吸收峰。通过经典的赝简谐振动理论很好地拟合了实验结果,分析了晶体中的横向光学声子振动模式,为氧化镁单晶在宽带太赫兹波段的应用提供了有益参考。The dielectric properties of single-crystal MgO were studied by terahertz time-domain spectroscopy in the frequency range extending from 0.5 to 9.5 THz. The refractive index, power absorption, and the complex dielectric function were extracted from experimental data. At low terahertz frequencies band （〈2 THz）, the absorption coefficient was extremely low and increased with increasing frequency. Meanwhile the corresponding refractive index had low dispersion, increasing from 3.12 to 3.15. Two prominent resonances were observed at 3.16 THz and 8.11 THz and were well-described by a multiple-oscillator model through theoretical fitting. The interaction of incident photons and the transverse optical （TO） phonons in the crystal were studied and it gives good evidence to further applications in developing broadband terahertz components and terahertz spectroscopy.

关 键 词：氧化镁 太赫兹 复介电函数 光学声子振动 

分 类 号：O433[机械工程—光学工程]