中国激光, 2019, 46 (6): 0614008, 网络出版: 2019-06-14
基于倾斜波前技术的高能强场太赫兹辐射脉冲源 下载: 2176次
High-Energy Strong-Field Terahertz Pulses Based on Tilted-Pulse-Front Technique
图 & 表
图 2. 基于飞秒激光抽运的强太赫兹辐射脉冲源
Fig. 2. Intense terahertz sources based on femtosecond laser pumping
图 3. 基于倾斜波前技术的强太赫兹辐射脉冲的单脉冲能量和能量转化效率随年份的变化。(a)脉冲能量;(b)能量转化效率
Fig. 3. Terahertz single pulse energy and optical-to-terahertz energy conversion efficiency versus year for intense terahertz pulses generated by tilted-pulse-front technique. (a) Pulse energy; (b) energy conversion efficiency
图 4. 基于级联效应产生具有高能量转化效率的太赫兹辐射脉冲源的示意图
Fig. 4. Diagram of generation of terahertz emission pulses with high energy conversion efficiency based on cascading effect
图 5. 利用倾斜波前技术产生太赫兹辐射脉冲的典型实验装置图
Fig. 5. Typical experimental setup for terahertz emission based on tilted-pulse-front technique
图 7. 抽运飞秒激光脉冲的两种展宽方法示意图
Fig. 7. Schematic of two methods for stretching pumping femtosecond laser
图 8. 利用脉冲宽度为4 ps的飞秒激光脉冲产生中心频率为100 GHz的太赫兹辐射脉冲。(a)太赫兹辐射脉冲的能量和能量转化效率随抽运功率密度的变化关系;(b)太赫兹时域波形和对应的频谱(点为实验结果,红线为理论计算结果)
Fig. 8. Terahertz emission with central frequency of 100 GHz produced by 4 ps laser pulse. (a) Terahertz emission energy and its energy conversion efficiency versus pumping power density; (b) terahertz temporal waveform and its spectrum (shot dot: experimental; red line: theoretical prediction)
图 9. 窄脉冲高功率密度激发会降低太赫兹辐射脉冲能量转化效率。(a)优化抽运飞秒激光脉冲宽度;(b)优化抽运飞秒激光脉冲能量
Fig. 9. Decrease of energy conversion efficiency of teraherza pulse due to ultrashort high power density excitation. (a) Optimization of pumping pulse width; (b) optimization of pumping pulse energy
图 10. 倾斜波前技术中的非线性失真效应引起的聚焦光斑大小和位置的变化机理
Fig. 10. Mechanism for variations in spot size and position caused by nonlinear distortion effect in tilted-pulse-front technique
图 11. 利用反射式台阶镜实现波前倾斜的原理示意图
Fig. 11. Principle diagram of pulse-front-tilting realized by reflective step mirror
图 12. 几种倾斜波前装置中典型的成像系统。(a)单平凸透镜成像;(b)双水平柱透镜成像;(c)双平凸透镜的望远镜系统;(d)双柱透镜成像;(e)组合式三透镜成像
Fig. 12. Typical imaging setups in tilted-pulse-front setup. (a) Plano convex lens; (b) double horizontal cylindrical lens; (c) telescope system with double plano convex lens; (d) double cylindrical lens; (e) composite triple lens
图 13. 椭圆光斑抽运下的太赫兹产生示意图。(a)圆形光斑抽运;(b)椭圆光斑抽运;(c)椭圆光斑在晶体上的示意图
Fig. 13. Schematic of terahertz emission with elliptical beam pumping. (a) Circular beam pumping; (b) elliptical beam pumping; (c) schematic of elliptical beam inside crystal
图 14. 铌酸锂晶体在不同温度下的折射率和吸收系数。(a)非常光折射率;(b)非常光吸收系数;(c)寻常光折射率;(d)寻常光吸收系数
Fig. 14. Refractive indexes and absorption coefficients of congruent lithium niobite crystals under different crystal temperatures. (a) Refractive indexes of extraordinary light; (b) absorption coefficients of extraordinary light; (c) refractive indexes of ordinary light; (d) absorption coefficients of ordinary light
图 15. 冷却晶体后的高能量转化效率太赫兹辐射脉冲源产生。(a)能量转化效率随温度的变化曲线;(b)能量转化效率随抽运飞秒激光脉冲能量的变化曲线
Fig. 15. Highly efficient terahertz emission due to cooling of lithium niobite crystal. (a) Energy conversion efficiency versus temperature; (b) energy conversion efficiency versus pump energy
图 16. 100 K和300 K温度下的太赫兹时域波形和频谱图。(a)时域波形;(b)频谱
Fig. 16. Terahertz temporal waveforms and their corresponding spectra at 100 K and 300 K, respectively. (a) Temporal waveforms; (b) spectra
图 17. 聚焦后的高质量太赫兹辐射脉冲聚焦光斑。(a)太赫兹辐射脉冲光斑照片;光斑的(b)水平和(c)竖直方向直径
Fig. 17. Focused spot of terahertz beam with high quality. (a) Measured terahertz beam profile; beam diameters of spot in (b) horizontal and (c) vertical directions
图 18. 利用钇锂氟化物(YLF)激光器实现高能量太赫兹辐射脉冲。(a) YLF激光器抽运的太赫兹辐射脉冲能量输出;(b)对应的能量转化效率;(c)不同抽运飞秒激光脉冲功率密度下,剩余抽运飞秒激光脉冲的频谱展宽情况
Fig. 18. High-energy terahertz emission realized by Yttrium Lithium Fluoride (YLF) laser. (a) Extracted terahertz energy pumped by YLF laser; (b) corresponding energy conversion efficiency; (c) spectral broadening of residual pumping laser under different pump powers
表 1强太赫兹辐射脉冲源的能量转化效率和单脉冲能量世界纪录
Table1. World record of energy conversion efficiency and single pulse energy for intense terahertz sources
|
表 2基于倾斜波前技术产生强太赫兹辐射脉冲的抽运激光器参数
Table2. Pump laser parameters for intense terahertz pulses generated by tilted-pulse-front technique
|
吴晓君, 郭丰玮, 马景龙, 欧阳琛, 王天泽, 张保龙, 王暄, 李尚卿, 孔德胤, 柴姝愫, 阮存军, 苗俊刚, 李玉同. 基于倾斜波前技术的高能强场太赫兹辐射脉冲源[J]. 中国激光, 2019, 46(6): 0614008. Xiaojun Wu, Fengwei Guo, Jinglong Ma, Chen Ouyang, Tianze Wang, Baolong Zhang, Xuan Wang, Shangqing Li, Deyin Kong, Shusu Chai, Cunjun Ruan, Jungang Miao, Yutong Li. High-Energy Strong-Field Terahertz Pulses Based on Tilted-Pulse-Front Technique[J]. Chinese Journal of Lasers, 2019, 46(6): 0614008.