We experimentally demonstrate tight focusing of a spin wave beam excited in extended nanometer-thick films of yttrium iron garnet by a simple microscopic antenna functioning as a single-slit near-field lens. We show that the focal distance and the minimum transverse width of the focal spot can be controlled in a broad range by varying the frequency/wavelength of spin waves and the antenna geometry. The experimental data are in good agreement with the results of numerical simulations. Our findings provide a simple solution for the implementation of magnonic nanodevices requiring a local concentration of the spin-wave energy.We experimentally demonstrate tight focusing of a spin wave beam excited in extended nanometer-thick films of yttrium iron garnet by a simple microscopic antenna functioning as a single-slit near-field lens. We show that the focal distance and the minimum transverse width of the focal spot can be controlled in a broad range by varying the frequency/wavelength of spin waves and the antenna geometry. The experimental data are in good agreement with the results of numerical simulations. Our findings provide a simple solution for the implementation of magnonic nanodevices requiring a local concentration of the spin-wave energy.

中文翻译：

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超薄 YIG 薄膜中自旋波的亚微米近场聚焦

我们通过实验证明了通过用作单缝近场透镜的简单微型天线在纳米厚的钇铁石榴石薄膜中激发的自旋波束的紧密聚焦。我们表明，通过改变自旋波的频率/波长和天线几何形状，可以在很宽的范围内控制焦距和焦斑的最小横向宽度。实验数据与数值模拟结果吻合良好。我们的研究结果为实现需要局部集中自旋波能量的磁子纳米器件提供了一个简单的解决方案。我们通过一个简单的微观天线功能实验证明了在钇铁石榴石的扩展纳米厚膜中激发的自旋波束的紧密聚焦作为单缝近场镜头。我们表明，通过改变自旋波的频率/波长和天线几何形状，可以在很宽的范围内控制焦距和焦斑的最小横向宽度。实验数据与数值模拟结果吻合良好。我们的发现为实现需要局部集中自旋波能量的磁纳米器件提供了一个简单的解决方案。