Optical-induced dielectric tunability properties of DAST crystal in THz range
Optical-induced dielectric tunability properties of DAST crystal in THz range
复制标题
DAST 晶体在太赫兹范围内的光致介电可调特性
DOI：
10.1088/1674-1056/ab4e81
复制
发表时间：
2019
影响因子：
1.7
通讯作者：
Jianquan Yao
中科院分区：
文献类型：
--
作者：
Degang Xu;Xianli Zhu;Yuye Wang;Jining Li;Yixin He;Zi-Bo Pang;Hongjuan Cheng;Jianquan Yao
实验研究了DAST晶体在THz波段的光致介电调谐特性。采用自发成核法生长了DAST晶体，并对其进行了红外光谱表征。采用太赫兹时域光谱法（THz-TDS），在室温下，利用最佳激发光场波长，测量了不同功率下532 nm激光激发DAST晶体的透射谱。当光场为80 mW时，在0.68 THz处，透射THz强度降低了26%.同时，折射率随激发光场的变化呈现近似二次曲线，这与光生载流子在DAST晶体中引起光折变现象的内部空间电荷场有关。由于DAST晶体中光生载流子的吸收效应，在0.68 THz处THz吸收系数显著增强13.7%。
The optical-induced dielectric tunability properties of DAST crystal in THz range were experimentally demonstrated. The DAST crystal was grown by the spontaneous nucleation method (SNM) and characterized by infrared spectrum. With the optimum wavelength of the exciting optical field, the transmission spectra of the DAST crystal excited by 532 nm laser under different power were measured by terahertz time-domain spectroscopy (THz-TDS) at room temperature. The transmitted THz intensity reduction of 26 % was obtained at 0.68 THz when the optical field was up to 80 mW. Meanwhile, the variation of refractive index showed an approximate quadratic behavior with the exciting optical field, which was related to the internal space charge field of photorefractive phenomenon in the DAST crystal caused by the photogenerated carrier. A significant enhancement of 13.7 % for THz absorption coefficient occurred at 0.68 THz due to the photogenerated carrier absorption effect in the DAST crystal.