Summary
Over the past fifty years, Moore's Law has guided nanotechnology towards the miniaturization of components across all three dimensions: x, y, and z. As we near its limits in 2025, our laboratory is investigating a novel form of nanotechnology with components that extend over large distances in the x and y dimensions while maintaining nanoscale thickness in the z dimension. These extreme-aspect-ratio nanostructures possess a unique blend of macro- and nano-features, exhibiting properties absent in their smaller-scale equivalents. High-aspect-ratio mechanical resonators are crucial for precision sensing, ranging from macroscopic gravitational wave detectors to nanoscale acoustics. Nevertheless, fabrication difficulties and significant computational expenses have restricted the length-to-thickness ratio of these devices, leaving a substantial area in nano-engineering unexplored. We introduce, for the first time, nanomechanical resonators that extend several centimeters in length while maintaining nanometer-scale thickness. We investigate this novel design space using an optimization approach that strategically utilizes rapid millimeter-scale simulations to guide the more computationally demanding centimeter-scale design optimization. The combination of nanofabrication, machine learning-guided design optimization, and precision engineering paves the way for a solid-state approach to room temperature quality factors of 10 billion at kilohertz mechanical frequencies—comparable to the extreme performance of top cryogenic resonators and levitated nanospheres, even under much less stringent temperature and vacuum conditions. Advancing this nanotechnology will necessitate a convergence of new physics insights, innovative structural engineering, and advanced material science.
