Designing an Acoustic Diode

Urbana/ B. Liang<br><br>Schematic illustration of “acoustic diode” made of a zero refractive-index medium (ZIM) prism, which only allows the acoustic waves comes from the left (“positive incidence”) to pass but blocks the waves from right (“negative incidence”).<br>

Most people know about ultrasound through its role in prenatal imaging: those grainy, grey outlines of junior constructed from reflected sound waves. A new technology called an “acoustic diode,” envisioned by researchers in China's Nanjing University, may dramatically improve future ultrasound images by changing the way sound waves are transmitted.

In the journal Applied Physics Letters, which is produced by AIP Publishing, the scientists describe the theoretical framework for an acoustic diode — a device that achieves a one-way transmission of sound waves much the same as an electrical diode controls the one-way transmission of electrical impulses.

The one-way flow of sound would provide brighter and clearer ultrasound images by eliminating acoustic disturbances caused by sound waves going in two directions at the same time and interfering with each other, explained researcher Jian-chun Cheng.

“The propagation direction of the output wave would be controlled freely and precisely,” Cheng said. “These features are crucial for the medical ultrasound applications of the resulting devices.”

How the Acoustic Diode Would Work

Sound waves easily flow in two directions. Yet in nature, total reflection of sound in one direction is known to occur at the air-water interface. This gave investigators the idea that an acoustical diode could be constructed by transmitting acoustic waves using an asymmetric prism to create total unidirectional reflection.

The team developed its theoretical model based on a material not found in nature called a near-Zero Index Metamaterial (ZIM) and a prism to create high transmission efficacy acoustic waves that strike a reflective boundary from two opposite sides.

In theory, explained Dr. Cheng, “This would produce a unique tunneling effect and an unprecedented property that the output waveform is kept consistent with those of the waves traveling toward a boundary. “

The article, “Unidirectional acoustic transmission through a prism with near-zero refractive index” by Yong Li, Bin Liang, Zhong-ming Gu, Xin-ye Zou and Jian-chun Cheng appears in the journal Applied Physics Letters. See: http://dx.doi.org/10.1063/1.4817249

ABOUT THE JOURNAL
Applied Physics Letters features concise, rapid reports on significant new findings in applied physics. The journal covers new experimental and theoretical research on applications of physics phenomena related to all branches of science, engineering, and modern technology. See: http://apl.aip.org

Media Contact

Jason Socrates Bardi Newswise

More Information:

http://www.aip.org

All latest news from the category: Physics and Astronomy

This area deals with the fundamental laws and building blocks of nature and how they interact, the properties and the behavior of matter, and research into space and time and their structures.

innovations-report provides in-depth reports and articles on subjects such as astrophysics, laser technologies, nuclear, quantum, particle and solid-state physics, nanotechnologies, planetary research and findings (Mars, Venus) and developments related to the Hubble Telescope.

Back to home

Comments (0)

Write a comment

Newest articles

Perovskite solar cells soar to new heights

Metal halide perovskites have been under intense investigation over the last decade, due to the remarkable rise in their performance in optoelectronic devices such as solar cells or light-emitting diodes….

Blue hydrogen can help protect the climate

An international group of researchers led by the Paul Scherrer Institute and the Heriot-Watt University has carried out in-depth analyses of the climate impact of blue hydrogen. This is produced…

Genes associated with hearing loss visualised in new study

Researchers from Uppsala University have been able to document and visualise hearing loss-associated genes in the human inner ear, in a unique collaboration study between otosurgeons and geneticists. The findings…

Partners & Sponsors