Porous rubber microbeads suspended in a gel are found to exhibit a negative acoustic index of refraction, which makes these metamaterials promising for underwater acoustic applications. Figure 1: ...

Scientists have demonstrated that negative refraction can be achieved using atomic arrays -- without the need for artificially manufactured metamaterials. Scientists have long sought to control light ...

Two physicists in China have shown that it should be possible to observe negative refraction with sound waves. Xiangdong Zhang of Beijing Normal University and Zhengyou Liu of Wuhan University have ...