Researchers have found a way of using nanomaterials to come up with the very first power-free frequency tuning ever since the invention of the radio. This paper, which was authored by researchers from the University of Oxford and the University of Pennsylvania, was published recently in Nature Communications

Matching the frequencies of transmitters and receivers is essential to telecommunications technology. This happens when the receivers and transmitters tune in to the same frequency channel. In the wide network of communication in the present era, it is vital to have the ability to synthesize many frequencies reliably and to quickly shift from one to another in order to achieve seamless connectivity.  

The authors of this research have come up with a different way of tuning the frequency of resonators. Their approach is quite different from the usual that uses mechanical stress on the nanostrings, as applied in guitar tuning through the pegs. The latter translates to more power consumption as voltage would be needed to maintain the tension.

In this study, the researchers used vibrating nanostrings of a chalcogenide glass that resonate at preplanned frequencies. The frequency of these resonators was tuned by switching the material’s atomic structure, which consequently alters the material’s mechanical stiffness.  

The nanowire initially possesses a crystalline structure which means high stiffness. This would consequently produce a higher resonance frequency. The crystalline structure is altered by sending an electrical impulse which changes its structure into an amorphous state. This means lower stiffness which generates lower resonance frequency. Using another electrical pulse, the atomic structure could be switched back to its original crystalline state. Once the crystal structure changes, this state could be maintained for years and years at room temperature. This means power-free tuning. 

Not only is it power-free. This is also super fast. Utku Emre Ali, who completed this study as part of his doctoral research, explained that Young’s modulus (a measure of stiffness) is changed by changing how atoms bond in these glasses at the speed of a few nanoseconds. This, in effect, would directly impact the frequency at which the nanostrings vibrate. 

The unique mechanism by which the atomic structure of the nanomaterials is altered was first discovered more than a decade ago by Professor Ritesh Agarwal at the University of Pennsylvania. Professor Agarwal, who also worked as a collaborator in the recent study, shared that it was a humbling experience that their fundamental work would have such an interesting demonstration more than 10 years after the first discovery. 

Meanwhile, Professor Harish Bhaskaran, who led this endeavor, explained that the study developed a new framework that uses functional materials whose mechanical properties could be altered with an electrical pulse. 

According to the engineer’s estimates, this approach could be a million times more efficient than commercial frequency synthesizers and faster by 10 to 100 times. These initial results might mean a future of higher data rates with lasting batteries.

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