Tamulienė Viktorija, Juškevičiūtė Greta, Buožius Danas, Vaičaitis Virgilijus, Babushkin Ihar, Morgner Uwe
Laser Research Center, Vilnius University, Saulėtekio 10, 10223, Vilnius, Lithuania.
Institute of Quantum Optics, Leibniz University of Hannover, Hannover, Germany.
Sci Rep. 2020 Oct 15;10(1):17437. doi: 10.1038/s41598-020-74263-x.
Here we present an experimental as well as theoretical study of third-harmonic generation in tightly focused femtosecond filaments in air at the wavelength of [Formula: see text]. At low intensities, longitudinal phase matching is dominating in the formation of 3rd harmonics, whereas at higher intensities locked X-waves are formed. We provide the arguments that the X-wave formation is governed mainly by the tunnel-like ionization dynamics rather than by the multiphoton one. Despite of this fact, the impact of the ionization-induced nonlinearity is lower than the one from bound-bound transitions at all intensities.
在此，我们展示了在空气中波长为[公式：见原文]的紧聚焦飞秒细丝中三次谐波产生的实验及理论研究。在低强度下，纵向相位匹配在三次谐波的形成中起主导作用，而在较高强度下会形成锁定的X波。我们提出论据表明，X波的形成主要由类隧道电离动力学而非多光子动力学所支配。尽管如此，在所有强度下，电离诱导的非线性的影响都低于束缚-束缚跃迁产生的影响。
