There are many glorious science-based terms when it comes to surfing. We all talk about swells, of course, the underwater energy that creates a breaking wave. But we'll look at swell angles and ...

Figure 1: Schematics of the degenerate 4WM process on a thin nonlinear film. In this Letter, we experimentally demonstrate nonlinear optical negative refraction in thin metallic nanostructures. We use ...

Whether a sound wave is reflected, refracted, or absorbed depends on the densities of the materials either side of the boundary. If the densities are very different then reflection is more likely.