Optimization of single-cycle terahertz generation in LiNbO3 for sub-50 femtosecond pump pulses.
Optimization of single-cycle terahertz generation in LiNbO3 for sub-50 femtosecond pump pulses.
复制标题
DOI：
10.1364/oe.21.006826
复制
发表时间：
2013-03
期刊：
影响因子：
3.8
通讯作者：
M. Kunitski;M. Richter;M. Thomson;A. Vredenborg;Jian Wu;T. Jahnke;M. Schöffler;H. Schmidt-Böcking-H.-Schmidt-Böckin
中科院分区：
文献类型：
--
作者：
M. Kunitski;M. Richter;M. Thomson;A. Vredenborg;Jian Wu;T. Jahnke;M. Schöffler;H. Schmidt-Böcking-H.-Schmidt-Böckin
从理论和实验上比较了不同的倾斜脉冲前沿泵浦方案在LiNbO（3）晶体中产生单周期THz的转换效率。已经发现，在低于50 fs的泵浦脉冲的情况下，具有单个透镜作为成像元件的常规设置是非常低效的，这主要是由于所产生的色差。这些像差是避免在建议的新的设置，它采用了两个凹面镜在开普勒望远镜的安排作为成像序列。这部分地补偿了球面像差，并导致了约。与单透镜设置相比，在35-fs光泵浦脉冲持续时间的情况下转换效率高六倍。使用0.5mJ泵浦脉冲获得了60 kV/cm的太赫兹场强。实验上已经发现太赫兹光束的发散度取决于所采用的泵浦成像方案。
We compare different tilted-pulse-front pumping schemes for single-cycle THz generation in LiNbO(3) crystals both theoretically and experimentally in terms of conversion efficiency. The conventional setup with a single lens as an imaging element has been found to be highly inefficient in the case of sub-50 fs pump pulses, mainly due to the resulting chromatic aberrations. These aberrations are avoided in the proposed new setup, which employs two concave mirrors in a Keplerian telescope arrangement as the imaging sequence. This partially compensates spherical aberrations and results in a ca. six times higher conversion efficiency in the case of 35-fs optical pump pulse duration compared to the single-lens setup. A THz field strength of 60 kV/cm was obtained using 0.5 mJ pump pulses. The divergence of the THz beam has been found experimentally to depend on the pump imaging scheme employed.