Feasible Conditions for Magnetostatic Wave Envelope Solitons and Their Formation under Optimal Conditions

虽然钇铁石榴石（YIG）薄膜由于其较窄的铁磁共振线宽而被广泛用于微波谐振器，但它不足以使静磁波（MSW）包络孤子在YIG薄膜上几乎没有传播损耗地传播。本文用具有三阶色散和耗散效应的非线性薛定谔方程来描述固体固体包络孤子。采用分步傅里叶法求解了NLS方程。为了在实验中观察到类孤子的行为，我们必须使固体固体废物的色散足够高，使输入脉冲的波形能够发生足够快的变化，并在耗散效应盛行之前完成固体固体废物孤子的形成。另一方面，色散越强，形成孤子所需的功率就越大。通过对固体固体孤子衰减特性的定量研究，讨论了固体固体孤子形成和传播的可行条件。研究发现，MSW波包的幅值衰减率与输入功率有关，其全宽半宽加宽率也与输入功率有关，需要强调的是，输入功率的增加进一步证明对MSW孤子的阻尼有影响，相当于损耗的减少。通过在薄膜表面放置金属平面或金属光栅来控制其色散，可以形成静磁表面波（MSSW）亮孤子。在YIG薄膜中使用所谓的孤子效应已被证明是一种有前途的技术，可以产生至少短至1ns的静磁波（MSW）脉冲。

Although yttrium iron garnet (YIG) films are widely used for microwave resonators owing to their narrow ferromagnetic resonance linewidth, it is not enough narrow for the magnetostatic wave (MSW) envelope solitons to propagate on the YIG films almost free of propagation losses.The nonlinear Schr_dinger (NLS) equation with the third order dispersion and dissipative effects has been used to describe MSW envelope solitons. The split-step Fourier method has been used to solve the NLS equation. In order to observe a soliton-like behavior in experiments, we must make the dispersion of the MSW so high that the waveform of an input pulse may make a sufficiently rapid change and the MSW soliton formation may be completed before the dissipative effect becomes prevailing. On the other hand, the stronger the dispersion, the more power is needed to form a soliton.Feasible conditions for MSW soliton formation and propagation have been discussed by quantitatively investigating the decay features of MSW solitons. The amplitude decay rate of MSW wave packets has been found to be dependent on the input power level, so is the broadening rate of their full-width at half maximum (FWHM), and it should be emphasized that the increase of input power has further been proved to have an effect on the damping of MSW solitons which is equivalent to the decrease of loss.The magnetostatic surface wave (MSSW) bright solitons can be formed if the dispersion is controlled by putting a metal plane close to or a metal grating on the surface of a YIG film.The use of so-called soliton effects in a YIG film has been shown to be a promising technique for production of magnetostatic wave (MSW) pulses with at least as short width as 1 ns.