If earbuds can do everything you can already do with your smartphone, how about doing more? That sounds a bit like science fiction, but it might not actually be that far off. A new class of synthetic materials could usher in the next revolution in wireless technology, allowing devices to become smaller, require less signal strength, and consume less power.
The key to these advances lies in what experts call phononics, something similar to photonics. Both utilize similar laws of physics and offer new ways to advance technology. Photonics uses photons, or light, while phononics does the same thing as phonons. Phonons are physical particles that transmit mechanical vibrations through matter, similar to sound, but at frequencies too high to be heard.
In a paper published in Nature Materials, researchers from the University of Arizona’s Wyant College of Photonic Sciences and Sandia National Laboratories report a major milestone toward real-world applications based on phononics. . By combining highly specialized semiconductor materials with piezoelectric materials that are not normally used together, the researchers were able to generate massive nonlinear interactions between phonons. Together with previous innovations that demonstrated amplifiers for phonons using the same materials, this opens the possibility of making wireless devices such as smartphones and other data transmitters smaller, more efficient, and more powerful. It will be done.
“Most people would be surprised to hear that there are about 30 filters in a mobile phone whose only job is to convert radio waves into sound waves and back again,” the study said. said Matt Eikenfield, senior author and co-appointer. at Arizona College of Photonic Sciences and Sandia National Laboratories in Albuquerque, New Mexico.
These piezoelectric filters, part of what’s known as a front-end processor, are built on special microchips and are needed to convert sound and radio waves multiple times each time a smartphone sends or receives data, he said. said. They can’t be made from the same material (such as silicon) as other critical chips in front-end processors, making the physical size of the device larger than necessary, and in the process, Eikenfield said. The round trip between radio waves and sound waves causes loss, which accumulates and degrades performance.
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“Normally, phonons behave completely linearly, meaning they don’t interact,” he says. “It’s like shining one laser pointer beam onto another laser pointer beam. They just pass through each other.”
Nonlinear phononics refers to what happens in special materials when phonons can and do interact, Eichenfield said. In their paper, the researchers demonstrated what he called a “giant phononic nonlinearity.” The synthetic material the researchers created produced much stronger interactions between phonons than any conventional material.
“To use a laser pointer analogy, this is like changing the frequency of the photons in the first laser pointer when you turn on the second laser pointer,” he said. “As a result, you will see the first beam change color.”
Using a new phononics material, researchers have demonstrated that one beam of phonons can actually change the frequency of another beam. Furthermore, they showed that phonons can be manipulated in ways that were previously possible only with transistor-based electronics.
The group creates all the components needed for a radio frequency signal processor on a single chip, using sonic technology instead of transistor-based electronics, in a manner compatible with standard microprocessor manufacturing. We have been working towards this goal and our latest publication is proof of that. That means it can be done. Researchers have previously succeeded in producing audio components, including amplifiers and switches. The last piece of the puzzle has been added with the acoustic mixer described in the latest publication.
“Now we can point to all the components on a diagram of a high-frequency front-end processor and say, ‘Oh, we can create all of these on one chip using sound waves,'” Eikenfield said. said. “We’re ready to create a whole shebang in the acoustic realm.”
Eichenfield said devices such as cell phones and other wireless communications equipment could be made up to 100 times smaller by putting all the components needed to create a radio frequency front end on a single chip. It is said that there is a sex.
The researchers achieved a proof of principle by combining highly specialized materials into a microelectronic-sized device and transmitting sound waves into it. Specifically, a silicon wafer with a thin layer of lithium niobate, a synthetic material widely used in piezoelectric devices and mobile phones, is coated with an ultrathin layer (less than 100 atoms thick) of a semiconductor containing indium gallium arsenide. Added.
“By combining these materials in the right way, we were able to experimentally access a new realm of sonic nonlinearity,” said Sandia engineer Lisa Hackett, lead author of the paper. Ta. “This means we have a path forward to invent high-performance technologies for transmitting and receiving radio waves smaller than what was previously possible.”
In this setting, sound waves traveling through the system behave nonlinearly as they travel through the material. You can use this effect to change frequencies or encode information. Nonlinear effects, a staple of photonics, have been used for years to turn things like invisible laser light into visible laser pointers, but their use in phononics has been hampered by technological and material limitations. . For example, lithium niobate is one of the most nonlinear phononic materials known, but when used alone its nonlinearity is very weak, hampering its usefulness in technological applications.
By adding indium gallium arsenide semiconductors, Eichenfield’s group creates an environment in which sound waves traveling through the material affect the charge distribution within the indium gallium arsenide semiconductor film, mixing them in specific and controllable ways. Ta. , opening up the system to a variety of applications.
“The effective nonlinearity that can be generated in these materials is hundreds or even thousands of times larger than what was previously possible. This is incredible,” Eikenfield said. . “If we could do the same thing with nonlinear optics, it would revolutionize the field.”
According to the authors, physical size is one of the fundamental limitations of current state-of-the-art high-frequency processing hardware, and new technology opens the door to electronics that are even more capable than their current counterparts. There is a possibility that it will open. Communication devices that take up virtually no space, have better signal coverage, and longer battery life are on the horizon.
reference: Hackett L, Koppa M, Smith B et al. Giant electron-mediated phononic nonlinearity in semiconductor-piezoelectric heterostructures. nut meter. 2024.Doi: 10.1038/s41563-024-01882-4
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