红外与毫米波学报, 2019, 38 (4): 04485, 网络出版: 2019-10-14
基于DAST晶体的高能量超宽带可调谐小型化差频THz辐射源研究
High-energy, ultra-wideband tunable and compact terahertz source based on DAST crystal via difference frequency generation
摘要
基于双温区法生长的高质量DAST(4-(4-二甲基氨基苯乙烯基)甲基吡啶对甲苯酸盐)晶体,成功搭建了高能量、超宽带可调谐差频THz辐射源,系统尺寸40 cm×25 cm,调谐范围达到0.3~19.6 THz,最大输出能量达到4.02 μJ/pulse@18.6 THz,信噪比最高达到32.24 dB,结合振镜扫描技术,以0.1 THz为步长,超宽带光谱扫描时间小于1 min.实验中观测到差频产生THz波的输出饱和现象并研究了基于DAST晶体差频产生THz波的偏振特性与传输特性,证明基于DAST晶体差频产生的THz波消光比达到0.05,且差频过程满足0类相位匹配条件.基于该太赫兹辐射源,对多种固体样品在2~14 THz范围内的超宽带THz光谱信息进行了有效获取.
Abstract
We have demonstrated a compact, high-energy and broadly tunable monochromatic terahertz (THz) source with the dimensional size of 40 cm×25 cm, based on difference frequency generation (DFG) in 4-N,N-dimethylamino-4′-N′-methybazoliumtoyslate (DAST) crystal, grown in two-zone growth method. The THz frequency was tuned randomly and rapidly in the range of 0.3~19.6 THz due to the widely tunable KTP-OPO and galvano-optical beam scanner. The highest pulse energy of 402 μJ was obtained at 18.6THz in our system. And the highest signal to noise ratio of 32.24 dB was realized at 4.3 THz using 4K-Bolometer detector. Furthermore, the characteristics of THz polarization and divergence angle were measured experimentally. Saturation phenomenon for THz output was observed and studied. Moreover, the transmission THz spectroscopies of materials in solid state were measured with the ultra-wideband tunable THz source based on DAST crystal.
贺奕焮, 庞子博, 朱先立, 徐德刚, 王与烨, 孟大磊, 武聪, 程虹娟, 徐永宽, 姚建铨. 基于DAST晶体的高能量超宽带可调谐小型化差频THz辐射源研究[J]. 红外与毫米波学报, 2019, 38(4): 04485. HE Yi-Xin, PANG Zi-Bo, ZHU Xian-Li, XU De-Gang, Wang Yu-Ye, MENG Da-Lei, WU Cong, CHENG Hong-Juan, XU Yong-Kuan, YAO Jian-Quan. High-energy, ultra-wideband tunable and compact terahertz source based on DAST crystal via difference frequency generation[J]. Journal of Infrared and Millimeter Waves, 2019, 38(4): 04485.