Nanoresonators: the plot thickens amid new insights

A team of researchers from Leti along with three of Leti’s international partners* have finally shed new light on the discrepancy of up to two orders of magnitude between the theoretical detection limits of nanoresonators and the resonators’ actual performance.

Until now, it was believed that the tiniest mass or force that could be detected by a nanoresonator depended on temperature fluctuations in the resonator’s environment. Given that state-of-the-art resonators offer sensitivities of 10-21 gram, the theory was plausible.

In research published in Nature Nanotechnology, a Grenoble-based team of researchers demonstrated that the nanoresonator’s own frequency plays a much greater role than environmental factors. In other words, the “background noise” once thought to be the main culprit of performance problems is actually not as significant as the noise from the system itself.
 

One resonator, two frequencies

The researchers developed and patented a technique that simultaneously exposes the nanoresonator to two frequencies close to the system’s resonant frequency. They then used the return signal to determine the influence of measurement noise and that of fluctuations in the resonant frequency.

While the research did provide new insights into the discrepancies between theoretical and actual detection limits, there is still much to uncover. The researchers tested the various theories in the literature—temperature gaps, trapped charge, diffusion of gas molecules on the resonator’s vibrating cantilever—to no avail. They still don’t know why the resonant frequency fluctuates.

Leti is pursuing its investigations, hoping to solve the mystery and unlock the secrets to better nanoresonator performance.
 

*EPFL Lausanne, Indian Institute of Sciences, California Institute of Technology

Contact: sebastien.hentz@cea.fr

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