Opt Lett. 2018 Jul 1;43(13):3112-3115. doi: 10.1364/OL.43.003112.
We demonstrate numerically and experimentally that intense pulses propagating in gas-filled capillaries can undergo localization in space and time due to strong plasma defocusing. This phenomenon can occur below or above the self-focusing threshold P as a result of ionization-induced refraction that excites higher-order modes. The constructive interference of higher-order modes leads to spatiotemporal localization and resurgence of the intensity. Simulations show that this confinement is more prominent at shorter wavelength pulses and for smaller capillary diameters. Experiments with ultraviolet pulses show evidence that this ionization-induced refocusing appears below P and thus represents a mechanism for spatiotemporal confinement without self-focusing.
我们通过数值和实验证明，由于强等离子体散焦，强脉冲在充满气体的毛细管中传播时会在空间和时间上发生局域化。这种现象可以在自聚焦阈值 P 以下或以上发生，这是由于电离诱导的折射激发了更高阶模式。更高阶模式的建设性干涉导致强度的时空局域化和再生。模拟表明，这种限制在更短波长的脉冲和更小的毛细管直径下更为显著。利用紫外脉冲的实验证明，这种电离诱导的再聚焦出现在 P 以下，因此代表了一种没有自聚焦的时空限制机制。
