Researchers at the University of Bristol have developed a new type of acoustic metamaterial that can be used to create a spotlight of sound. The material, which is made from LEGO-like bricks, can be used to focus sound waves into a narrow beam, which could have a range of applications in areas such as medical imaging, non-destructive testing, and underwater communications.

The new acoustic metamaterial is made from a series of small plastic bricks, each of which is about the size of a postage stamp. The bricks are arranged in a specific pattern, which creates a structure that has a negative refractive index. This means that sound waves travelling through the material are bent in the opposite direction to normal.

By carefully designing the pattern of the bricks, the researchers were able to create a material that can focus sound waves into a narrow beam. This beam can be steered by changing the arrangement of the bricks, which makes it possible to create a spotlight of sound that can be moved around.

The researchers say that their new acoustic metamaterial could have a range of applications. For example, it could be used to focus ultrasound waves for medical imaging, or to detect cracks in materials for non-destructive testing. It could also be used for underwater communications, where the ability to focus sound waves over long distances is important.

The research is published in the journal Nature Communications.