Opt Express. 2023 Feb 27;31(5):7922-7932. doi: 10.1364/OE.476261.
We demonstrate a high average power terahertz time-domain spectroscopy (THZ-TDS) set-up based on optical rectification in the tilted-pulse front geometry in lithium niobate at room temperature, driven by a commercial, industrial femtosecond-laser operating with flexible repetition rate between 40 kHz - 400 kHz. The driving laser provides a pulse energy of 41 µJ for all repetition rates, at a pulse duration of 310 fs, allowing us to explore repetition rate dependent effects in our TDS. At the maximum repetition rate of 400 kHz, up to 16.5 W of average power are available to drive our THz source, resulting in a maximum of 24 mW of THz average power with a conversion efficiency of ∼ 0.15% and electric field strength of several tens of kV/cm. At the other available lower repetition rates, we show that the pulse strength and bandwidth of our TDS is unchanged, showing that the THz generation is not affected by thermal effects in this average power region of several tens of watts. The resulting combination of high electric field strength with flexible and high repetition rate is very attractive for spectroscopy, in particular since the system is driven by an industrial and compact laser without the need for external compressors or other specialized pulse manipulation.
我们展示了一种基于铌酸锂中倾斜脉冲前沿几何光学整流的高平均功率太赫兹时域光谱（THZ-TDS）设置，该设置由商业、工业飞秒激光器驱动，其重复率在 40 kHz-400 kHz 之间具有灵活性。驱动激光器在 310 fs 的脉冲持续时间内为所有重复率提供 41 µJ 的脉冲能量，使我们能够在 TDS 中探索重复率相关的影响。在最高重复率 400 kHz 时，高达 16.5 W 的平均功率可用于驱动我们的太赫兹源，从而产生最大 24 mW 的太赫兹平均功率，转换效率约为 0.15%，电场强度可达几十 kV/cm。在其他可用的较低重复率下，我们表明我们 TDS 的脉冲强度和带宽保持不变，表明在几十瓦的平均功率范围内，太赫兹的产生不受热效应的影响。这种高电场强度与灵活的高重复率的结合非常适合光谱学，特别是因为该系统由工业和紧凑型激光器驱动，不需要外部压缩机或其他专门的脉冲处理。
