Yb:YAG thin-disk regenerative amplifier laser system emitting > 500 W average power and and 800-fs long pulses with 50 mJ pulse energy at 1030 nm.

基于近红外激光脉冲下转换的超短THz脉冲相干源在过去几十年中取得了巨大的进展。这一进展使时间域太赫兹光谱学成为一种强大的工具，可用于广泛的应用。范围从物理学和化学中物质基本成分的时间动力学研究，到更多应用的主题，如毒品或爆炸物检测。然而，目前所有这些应用都受到始终缺乏发射具有高平均功率的能量太赫兹脉冲的源的强烈限制，特别是在频率区域[1-10太赫兹]。THz-TDS有限的平均功率意味着需要满足THz脉冲能量和重复率之间不受欢迎的折衷，这反过来又意味着要么放弃需要高能脉冲的研究线路，要么在少数情况下牺牲重复率。之所以会出现这些限制，是因为目前大多数太赫兹-TDS装置都是由近红外钛宝石激光系统驱动的，这些系统的平均功率仅限于几瓦。由于从近红外到太赫兹的转换效率通常不超过几个百分点，在太赫兹模式下要达到显著更高的平均功率，需要驱动具有更高平均功率的超快激光光源。因此，我们在这里申请一种基于薄片激光技术的最先进的近红外超快再生激光放大器(Yb：YAG，1030 nm)系统，它提供高重复频率(5-50 kHz)和非常高的脉冲能量(高达50MJ)的独特组合，因此运行时的平均功率(&GT；500 W)比它们的钛：Sa同行高两个数量级。该激光系统一方面将用于探索高重复频率下的双色成丝，以在[1-10太赫兹]区域产生宽带和强场太赫兹脉冲，而且还将用于利用铌酸锂中的标题脉冲前沿产生MJ级太赫兹脉冲。由于我们要购买的信号源具有独特的性能，我们预计将在[1-10 THz区域]获得功率级的宽带THz脉冲，并在&lt；1 THz区域获得前所未有的高重复率的高能量单周期THz脉冲。这将通过提供更高的脉冲能量来补充我们正在进行的高功率太赫兹光源的研究，从而使非线性太赫兹光谱领域的突破性研究成为可能，特别是在生物条件下的水和其他样品的非线性太赫兹光谱这一尚未探索的领域。

Coherent sources of ultrashort THz pulses based on down-conversion of near-infrared laser pulses have seen enormous progress in the last few decades. This progress has enabled time-domain THz spectroscopy to emerge as a powerful tool for a wide variety of applications. ranging from the study of temporal dynamics of fundamental constituents of matter in physics and chemistry, to more applied topics such as drug or explosives detection. However, all these applications are currently strongly limited by the consistent lack of sources emitting energetic THz pulses with high average power, particularly in the frequency region [1-10 THz]. A limited average power of THz-TDS means that an undesired compromise between THz pulse energy and repetition rate needs to be met, which in turn means either abandoning research lines where energetic pulses are needed, or sacrificing repetition rate in the few cases where this is a possibility. These limitations occur because most THz-TDS setups are nowadays driven by near infrared Ti:Sapphire laser systems, which are limited in average power to only few watts. Since the conversion efficiency from near infrared to THz does typically not exceed a few percent, reaching significantly higher average powers in the THz regime requires driving ultrafast laser sources with much higher average power.We are therefore applying here for a state-of-the-art near-infrared ultrafast regenerative laser amplifier (Yb:YAG, 1030 nm) system based on the thin disk laser technology, which provides a unique combination of high repetition rate (5 – 50 kHz) and very high pulse energy (up to 50 mJ), thus operating with two orders of magnitude higher average power (> 500 W) than their Ti:Sa counterparts. This laser system will be used on the one hand for exploring two-color filamentation at high-repetition rate for the generation of broadband and strong-field Terahertz pulses in the [1-10 THz] region, but also for generating mJ-class THz pulses at <1 THz using titled-pulse fronts in Lithium Niobate. Thanks to the unique performance of the source we target to purchase, we expect to achieve watt-level, broadband THz pulses in the [1-10 THz region] with >1 µJ pulse energy - performance which remains unpaired in a laboratory setting to the best of our knowledge - as well as record high-energy single-cycle THz pulses with unprecedented high repetition rate in the < 1 THz region. This will complement our ongoing research on high-power THz sources by providing significantly higher pulse energy, thus enabling groundbreaking research in the field of nonlinear THz spectroscopy, in particular in the unexplored field of nonlinear THz spectroscopy of water and other samples in biological conditions.