Can we use sound to create holograms you can actually feel?
Imagine a digital image that isn't just light, but a physical presence. Through the science of acoustic holography, researchers are using ultrasound waves to reshape space, allowing us to manipulate solids, liquids, and even gases without ever touching them.
Acoustic holography and levitation represent a frontier where sound transcends mere communication to become a tool for physical manipulation. By precisely controlling ultrasound waves, scientists can create complex 3D sound fields. These fields can exert radiation forces that converge at specific points, creating acoustic traps. These traps are capable of levitating a diverse range of materials, including powders, liquids, and even biological tissues, effectively allowing for containerless transportation and contact-free material handling.
The mechanism relies on the manipulation of acoustic waves to generate structures like 'acoustic tweezers,' 'twisters,' and 'bottle traps.' Traditionally, achieving three-dimensional movement required complex setups, such as two transducers facing each other to create a standing wave, or multiple arrays arranged in squares. However, recent advancements have demonstrated that a single-sided array can achieve simultaneous 3D trapping, translation, and rotation. This is accomplished by optimally adjusting the phase delays used to drive the transducers, creating unprecedented acoustic structures without the need for physical lenses or mechanical actuation.
The implications for human-computer interaction and industry are profound. In the realm of multi-sensory interfaces, this technology enables 'mid-air haptics,' where users can feel digital objects through ultrasound-induced sensations. In the biopharmaceutical sector, companies like AcoustoFab are developing contact-free robotic systems for laboratory automation, which is vital for sterile cell manipulation. Beyond industry, the ability to use non-invasive, sound-based interfaces offers potential benefits for trauma recovery by leveraging body awareness and interoception, providing a safe way for vulnerable populations to interact with digital systems.
Source: Can sound levitate objects and create holograms you can touch? with Sriram Subramanian
