NIST electromechanical circuit sets record-beating microscopic 'drum'

Physicists at the National Institute of Standards and Technology (NIST) have demonstrated an electromechanical circuit in which microwaves communicate with a vibrating mechanical component 1,000 times more vigorously than ever achieved before in similar experiments. The microscopic apparatus is a new tool for processing information and potentially could control the motion of a relatively large object at the smallest possible, or quantum, scale.

Colorized micrograph of NIST's aluminum drum, which is 15 micrometers in diameter and 100 nanometers thick. The drum is used in quantum information experiments and ultraprecise measurements of mechanical motion.Credit: A. Sanders/NIST

Described in the March 10 issue of Nature,* the NIST experiments created strong interactions between microwave light oscillating 7.5 billion times per second and a  "micro drum" vibrating at radio frequencies 11 million times per second. Compared to previously reported experiments combining microscopic machines and electromagnetic radiation, the rate of energy exchange in the NIST device-the "coupling" that reflects the strength of the connection-is much stronger, the mechanical vibrations last longer, and the apparatus is much easier to make.

Similar in appearance to an Irish percussion instrument called a bodhrán, the NIST drum is a round aluminum membrane 100 nanometers thick and 15 micrometers wide, lightweight and flexible enough to vibrate freely yet larger and heavier than the nanowires typically used in similar experiments.

"The drum is so much larger than nanowires physically that you can make this coupling strength go through the roof," says first author John Teufel, a NIST research affiliate who designed the drum. "The drum hits a perfect compromise where it's still microscale but you can couple to it strongly."

The NIST experiments shifted the microwave energy by 56 megahertz (MHz, or million cycles per second) per nanometer of drum motion, 1,000 times more than the previous state of the art.

"We turned up the rate at which these two things talk to each other," Teufel says.