Meyer F, Vogel T, Ahmed S, Saraceno C J
Opt Lett. 2020 May 1;45(9):2494-2497. doi: 10.1364/OL.386305.
We demonstrate terahertz (THz) generation using the tilted pulse front method in lithium niobate, driven at an unprecedented high average power of more than 100 W and at a 13.3 MHz repetition rate, provided by a compact amplifier-free mode-locked thin-disk oscillator. The conversion efficiency was optimized with respect to the pump spot size and pump pulse duration, enabling us to generate a maximum THz average power of 66 mW, which is, to the best of our knowledge, the highest reported to date from a laser-driven, few-cycle THz source. Furthermore, we identify beam walk-off as the main obstacle that currently limits the conversion efficiency in this excitation regime (with moderate pulse energies and small spot sizes). Further upscaling to the watt level and beyond is within reach, paving the way for linear and nonlinear high average power THz spectroscopy experiments with an exceptional signal-to-noise ratio at megahertz repetition rates.
我们展示了在铌酸锂中使用倾斜脉冲前沿方法产生太赫兹（THz）波，由紧凑的无放大器锁模薄盘振荡器提供前所未有的超过100 W的高平均功率和13.3 MHz的重复频率驱动。针对泵浦光斑尺寸和泵浦脉冲持续时间对转换效率进行了优化，使我们能够产生66 mW的最大太赫兹平均功率，据我们所知，这是迄今为止激光驱动的少周期太赫兹源所报道的最高值。此外，我们确定光束走离是目前限制这种激发方式（中等脉冲能量和小光斑尺寸）下转换效率的主要障碍。进一步扩大到瓦级及以上是可行的，为兆赫兹重复频率下具有卓越信噪比的线性和非线性高平均功率太赫兹光谱实验铺平了道路。
