Wang T-L, Kolesik M
Opt Lett. 2017 Oct 15;42(20):4195-4198. doi: 10.1364/OL.42.004195.
While there is a consensus that higher-order effects beyond χ are present also in high-intensity light-matter interactions, when and how they become apparent needs further study. The central question addressed in this Letter is whether it is possible to design a situation in which they show up before being completely masked by the electrons freed by a high-intensity field. The second question we attempt to answer is how much such observations, if and when feasible, can reveal about the nature of the nonlinear polarization. We answer the first question in the affirmative, but our comparative simulations indicate that distinguishing the higher-order nonlinearity from the third-order polarization can be extremely challenging. We also briefly discuss the implications for the interpretation of the measured values of the nonlinear index.
虽然人们普遍认为，在高强度光与物质相互作用中也存在超出χ的高阶效应，但它们何时以及如何变得明显仍需进一步研究。本信函所探讨的核心问题是，是否有可能设计一种情形，使这些高阶效应在被高强度场释放的电子完全掩盖之前就显现出来。我们试图回答的第二个问题是，如果可行的话，此类观测能够在多大程度上揭示非线性极化的本质。我们对第一个问题的回答是肯定的，但我们的对比模拟表明，将高阶非线性与三阶极化区分开来可能极具挑战性。我们还简要讨论了对非线性折射率测量值解释的影响。
