Linear and nonlinear diffraction of dipolar spin waves in yttrium iron garnet films observed by space- and time-resolved Brillouin light scattering
Linear and nonlinear diffraction of dipolar spin waves in yttrium iron garnet films observed by space- and time-resolved Brillouin light scattering
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通过空间和时间分辨布里渊光散射观察钇铁石榴石薄膜中偶极自旋波的线性和非线性衍射
DOI：
10.1103/physrevb.61.11576
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发表时间：
2000
影响因子：
3.7
通讯作者：
A. Slavin
中科院分区：
文献类型：
--
作者：
O. Büttner;Martin Bauer;S. Demokritov;Y. Kivshar;V. Grimalsky;Y. Rapoport;A. Slavin
利用一种新的空间和时间分辨布里渊光散射(BLS)技术研究了切向磁化石榴石薄膜中由条线天线激发的二维偶极自旋波的光束和脉冲的衍射。这项新技术是研究高时空分辨率二维自旋波传播的有效工具。详细研究了由于相速度和群速度的非共线性引起的静磁表面波的单向激发和后向体积静磁波(BVMSW)在两个择优方向的传播等线性效应。在非线性区域，研究了定常和非定常的自聚焦效应。结果表明，具有有限横向孔径的定常BVMSW光束的非线性衍射导致光束在一个空间点上的自聚焦。有限宽度(非稳态)BVMSW脉冲的绕射导致时空自聚焦，形成强局域二维波包(自旋波弹)。利用变分方法和二维非线性薛定谔方程的直接数值积分对衍射过程进行了数值模拟，很好地定性地描述了观察到的现象。
A new advanced space- and time-resolved Brillouin light scattering (BLS) technique is used to study diffraction of two-dimensional beams and pulses of dipolar spin waves excited by strip-line antennas in tangentially magnetized garnet films. The new technique is an effective tool for investigations of two-dimensional spin wave propagation with high spatial and temporal resolution. Linear effects, such as the unidirectional exci-tation of magnetostatic surface waves and the propagation of backward volume magnetostatic waves (BVMSW) in two preferential directions due to the non-collinearity of their phase and group velocities are investigated in detail. In the nonlinear regime stationary and non-stationary self-focusing effects are studied. It is shown, that non-linear diffraction of a stationary BVMSW beam, having a finite transverse aperture, leads to self-focusing of the beam at one spatial point. Diffraction of a finite-duration (non-stationary) BVMSW pulse leads to space-time self-focusing and formation of a strongly localized two-dimensional wave packet (spin wave bullet). Numerical modeling of the diffraction process by using a variational approach and direct numerical integration of the two-dimensional non-linear Schrodinger equation provides a good qualitative description of the observed phenomena.