Researchers from Moscow State University have proposed a method to engineer metamaterials with an artificially tuned speed of sound. This development was shared by the university’s press service and reflects a growing interest in controlling acoustic behavior through structured materials.
In contemporary physics, phonons are understood as quantized modes of vibrations that carry energy, including sound, through a material. Alongside this concept, phononic crystals emerge as engineered structures that can modify how sound waves travel, allowing designers to tailor acoustic properties for specific needs.
The team at MSU has advanced this field by introducing a two-dimensional photonic crystal framework and calculating its acoustic characteristics. They examined an isotropic crystal made from molten quartz, featuring a periodic array of round voids. Through careful modeling, the researchers determined the primary acoustic parameters, including the speed of sound, polarization, and the preferred directions for energy transport for all waves that propagate within the material.
One key result is that acoustic anisotropy—the variation of sound behavior with direction caused by internal inhomogeneities—depends on the geometry of the voids, specifically the ratio of the hole diameter to the unit cell period. The findings show that by selecting different geometries, it is possible to tune the main acoustic properties of the medium to suit particular objectives. This means it becomes feasible to steer sound not only along chosen directions but also to adjust how fast it travels, enabling a broad range of control over acoustic behavior.
According to one of the study’s authors, Natalia Polikarpova, these phononic crystals satisfy the requirements for developing acoustic–optical devices built around them. Such devices could include filters, deflectors, and modulators where a precise sound speed is essential for performance and efficiency.
The research article detailing these advancements is published in Materials journal, contributing to the ongoing exploration of how structured media influence wave propagation and open avenues for practical applications in sensing, imaging, and communications.
In related scientific dialogue, astronomers have discussed earlier discoveries concerning the observed movements of the interstellar object Oumuamua, illustrating how exploration in one field often echoes findings in another and reinforces the value of cross-disciplinary insight.