Acoustic Metamaterials

Acoustic metamaterials are specially engineered materials to shape sound. The prefix "meta", meaning "beyond", perfectly describes these unusual materials that can exhibit strange properties such as a negative refractive index. Our team is pursuing several projects related to the design, fabrication and evaluation of acoustic metamaterials.

Our latest review talks about a systematic approach one can take to fabricate and assemble acoustic metamaterials and phononic crystals. Alongside this, we built a reflective spatial sound modulator device that consists of 1024 rigidly ended square waveguides with sliding bottom surfaces, providing variable phase delays. We demonstrate the ability of the device to focus ultrasonic waves in air at different points in space, generate accurate pressure landscapes and perform multiplane holography. Finally, we are working on developing microfluidic acoustic metamaterials that combine MEMS and microfluidics technique for developing spatial sound modulators.

Example papers:

  1. Prat-Camps, J; Christopoulos, G; Hardwick, J; Subramanian, S; (2020) A Manually Reconfigurable Reflective Spatial Sound Modulator for Ultrasonic Waves in Air. Advanced Materials Technologies
  2. Choi, C., Bansal, S., M├╝nzenrieder, N., & Subramanian, S. (2020). Fabricating and Assembling Acoustic Metamaterials and Phononic Crystals. Advanced Engineering Materials, adem.202000988. doi:10.1002/adem.202000988
  3. Moeini, S., Memoli, G., & Subramanian, S. (2020). Realizing Caustics in Acoustic Fields. Journal of Physics: Conference Series, 1461, 012107. doi:10.1088/1742-6596/1461/1/012107.