In the realm of sound technology, a groundbreaking study has emerged that could redefine the way we interact with and manipulate acoustic waves. The research, titled “Systematic design and experimental demonstration of transmission-type multiplexed acoustic meta-holograms,” delves into the fascinating world of acoustic holograms, offering promising applications in sound-field reconstruction, particle manipulation, ultrasonic haptics, and therapy.
The study, spearheaded by a team of researchers including Yifan Zhu, Nikhil JRK Gerard, Xiaoxing Xia, Grant C. Stevenson, Liyun Cao, Shiwang Fan, Christopher M. Spadaccini, Yun Jing, and Badreddine Assouar, presents a comprehensive theoretical, numerical, and experimental investigation of multiplexed acoustic holograms. These holograms operate at both audio and ultrasonic frequencies, leveraging a rationally designed transmission-type acoustic metamaterial.
At the heart of this innovation lies the proposed meta-hologram, which is composed of two Fabry-Perot resonant channels per unit cell. This design enables the simultaneous modulation of the transmitted amplitude and phase at two desired frequencies. Unlike conventional acoustic metamaterial-based holograms, the design strategy here introduces a new degree of freedom—frequency—which can actively tailor holograms that are otherwise passive. This enhancement significantly increases the information encoded in acoustic metamaterials.
The practical implications of this research are profound. The team demonstrated the capabilities of multiplexed acoustic metamaterials by projecting two different high-quality meta-holograms at 14 kHz and 17 kHz, showcasing patterns of the letters “N” and “S.” Furthermore, they showcased two-channel ultrasound focusing and annular beam generation for incident ultrasonic frequencies of 35 kHz and 42.5 kHz.
This technological advance holds the potential to address rising challenges in acoustic metamaterials, architectural acoustics, and medical ultrasound. For instance, in architectural acoustics, these multiplexed acoustic meta-holograms could revolutionize sound design in concert halls and auditoriums, ensuring optimal sound quality and distribution. In the medical field, the precise control of ultrasonic waves could enhance diagnostic imaging and therapeutic procedures, offering more targeted and effective treatments.
The research not only pushes the boundaries of what is possible with sound technology but also opens up new avenues for innovation. By providing a new degree of freedom in the form of frequency modulation, it paves the way for more sophisticated and versatile applications in various sectors. As we stand on the brink of this acoustic revolution, the potential for transformative change in how we use and experience sound is both exciting and immense.
