Photonics Institute, TU Wien, Gusshausstrasse 27-387, A-1040 Vienna, Austria.
Physics Department, International Laser Center, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia.
Nat Commun. 2016 Sep 13;7:12877. doi: 10.1038/ncomms12877.
The physics of strong-field applications requires driver laser pulses that are both energetic and extremely short. Whereas optical amplifiers, laser and parametric, boost the energy, their gain bandwidth restricts the attainable pulse duration, requiring additional nonlinear spectral broadening to enable few or even single cycle compression and a corresponding peak power increase. Here we demonstrate, in the mid-infrared wavelength range that is important for scaling the ponderomotive energy in strong-field interactions, a simple energy-efficient and scalable soliton-like pulse compression in a mm-long yttrium aluminium garnet crystal with no additional dispersion management. Sub-three-cycle pulses with >0.44 TW peak power are compressed and extracted before the onset of modulation instability and multiple filamentation as a result of a favourable interplay between strong anomalous dispersion and optical nonlinearity around the wavelength of 3.9 μm. As a manifestation of the increased peak power, we show the evidence of mid-infrared pulse filamentation in atmospheric air.
强场应用的物理特性要求驱动激光脉冲既具有能量又极其短暂。虽然光学放大器、激光和参量可以提高能量，但它们的增益带宽限制了可达到的脉冲持续时间，需要额外的非线性光谱展宽来实现几个甚至单个周期的压缩和相应的峰值功率增加。在这里，我们在中红外波长范围内证明了一种简单的、节能且可扩展的类孤子脉冲压缩，在没有额外色散管理的情况下，在毫米长的钇铝石榴石晶体中实现了这一压缩。在调制不稳定性和多丝化开始之前，亚三周期脉冲被压缩并提取出来，这是由于在 3.9 μm 波长附近强反常色散和光学非线性之间的有利相互作用。作为峰值功率增加的表现，我们展示了在大气中中红外脉冲细丝化的证据。
