有机非线性光学晶体DAST及其在太赫兹领域的应用研究进展  

The research progress on organic nonlinear optical crystal DAST and its application in Teraherz region

作　　者：马玉哲 钟德高[1] 曹丽凤[1] 纪少华 郝伦[1] 唐捷[1] 滕冰[1] 

机构地区：[1]青岛大学物理科学学院,青岛266071

出　　处：《中国科学：技术科学》2017年第11期1165-1176,共12页Scientia Sinica(Technologica)

基　　金：国家自然科学基金(批准号:11374170;51402159);山东省重点研发计划(编号:2015GGX102020);山东省泰山学者计划资助项目

摘　　要：主要介绍DAST晶体的基本结构和物理性能参数,几种不同生长方法及基于有机DAST晶体通过光学差频法产生THz波.重点研究了基于DAST晶体利用光学差频法产生太赫兹(THz)波过程中,泵浦光源的双波长调谐范围及光束质量对THz调谐范围及转换效率的影响,及其利用光整流法产生THz波的过程中,泵浦光(飞秒激光的波长、脉冲宽度和能量)对THz脉冲输出能量和转换效率的影响.综合分析影响THz辐射性能的因素及其获得大尺寸高质量晶体的主要挑战.本课题组在系统分析利用自发成核、斜板、籽晶和双温区法生长晶体优缺点的基础上,利用自发成核结合顶部籽晶法生长出高质量、尺寸为25 mm×22 mm×2 mm的晶体.下一步计划从晶体生长和泵浦光束的质量两方面改善THz输出能量及光-THz波转换效率.This article mainly introduces the basic structure and physical performance parameters, several kinds of growth methods about 4-N,N-dimethylamino-4-N-methyl stilbazolium tosylate（DAST） crystal, and generating THz wave based on DAST crystal by optical difference frequency method. The dual wavelength tuning range and beam quality of optical pump sources have an important impact on the conversion efficiency and tuning range of THz in the generation of THz radiation based on DAST crystal by the optical difference frequency（DFG）. In addition, the influences of optical pump（the wavelength of femtosecond laser, pulse width and energy） to the THz pulse output enengy and conversion efficiency in the process of generating THz using optical rectification（OR） were also reported.The influence factors of THz radiation and main challenges in the process of growing high quality and large size DAST crystal have been analyzed comprehensively. Bulk single crystal were grown with dimensions of 25 mm×22 mm×2 mm using the slope nucleation coupled with seed crystal method in our present work on systematic analyzing the advantages and disadvantages of spontaneous nucleation method, slope nucleation method, seed crystal method and two zone growth method. Next, we expect to improve laser-THz conversion efficiency and the THz radiation energy by optimizing the process of crystal growth and improving the quality of optical pump.

关 键 词：DAST晶体 晶体生长 太赫兹(THz) 差频法 光整流法 

分 类 号：O441[理学—电磁学] O734[理学—物理]