By nanostructuring one of two interacting metal surfaces at scales below the plasma wavelength, a new regime in the Casimir force was observed by Argonne National Laboratory researchers in the Center for Nanoscale Materials Nanofabrication & Devices Group working with collaborators at NIST, other national laboratories, and universities. Replacing a flat surface with a deep metallic lamellar grating with <100 nm features strongly suppresses the Casimir force and, for large intersurface separations, reduces it beyond what is theoretically predicted.
The new Casimir force regime is significantly different from the well-known attraction between parallel plates and is characterized by a crossover from enhancement to strong reduction of the Casimir force. Manipulation of the Casimir force has potential technological applications in micro- and nanoelectromechanical systems switches, quantum computing, and searches for non-Newtonian gravity.
CNM's state-of-the-art lithography capabilities combined with plating technology were critical to the experimental configuration. The Casimir force was measured between a gold sphere and a nanostructured metal grating. An optical fiber monitored the distance to a supporting substrate, and an oscillator measured the Casimir interaction.
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More information: F. Intravala et al., "Strong Casimir force reduction through metallic surface nanostructuring," Nature Communications, 4, 2515 (2013). DOI: 10.1038/ncomms3515