We report our experimental observation of a single and stable defect mode arising in the non-Bragg bandgap of surface water waves by introducing a defect element into a water channel with periodically corrugated sidewalls. By investigating the existence of the non-Bragg defect mode and its frequency shifting, we find that unlike the Bragg defect mode which arises within an extended region around the Bragg gap in the spectrum, the non-Bragg type defect mode exists within a much smaller region. It is further proved by the experiments that the frequency shifting property of the defect mode in the non-Bragg gap is comparable to that of the Bragg type. The results show that the location of the defect mode in the bandgap is dependent on the length of the defect element. The ability to tune the defect modes for surface water waves would guide existing and next-generation wave energy control and coastal protection technologies.

我们报告了通过将缺陷元素引入具有周期性波纹侧壁的水通道中，在地表水波的非布拉格带隙中产生的单一且稳定的缺陷模式的实验观察。通过研究非布拉格缺陷模式的存在及其频移，我们发现与在光谱中布拉格间隙周围的扩展区域内出现的布拉格缺陷模式不同，非布拉格型缺陷模式存在于一个小得多的区域内。地区。实验进一步证明了非布拉格能隙中缺陷模式的频移特性与布拉格型相当。结果表明，带隙中缺陷模式的位置取决于缺陷元素的长度。