Researchers reveal quantum advantage that could advance future sensing devices

Researchers at the Department of Energy’s Oak Ridge National Laboratory have taken a big step forward in using quantum mechanics to improve sensing devices, a new advance that could be used in a wide range of fields , including materials characterization, imaging improvement, and biological and medical applications. .

Quantum mechanics is how we understand extremely small objects that exhibit characteristics of particles and waves. Its application to improve sensing devices aims to obtain more precise measurements that would not otherwise be accessible. Quantum sensing is used in a variety of challenging environments and applications, including detecting oil leaks in underwater pipelines, probing biological samples, improving medical devices, and detecting dark matter throughout the universe.

Scientists from ORNL and the University of Oklahoma have used the unique properties of quantum states of light to implement enhanced quantum sensing in parallel. The type of light used in this experiment is in compressed states that have less noise than conventional light or light whose electromagnetic wavelengths are visible to the human eye.

These results open the door to improved, highly parallel spatially resolved quantum sensing techniques and complex quantum sensing and quantum imaging platforms. This research builds on previous work on quantum-enhanced plasmonic sensing using quantum light, which found that plasmonic sensors could be enhanced with quantum light.

The results of the study were published in the journal ACS Photonics.

As part of their experiments to better exploit the quantum properties of light for sensing, the researchers used bright twin beams of light to probe a quadrant quadrant plasmonic array, a sensing system made up of four individual sensors arranged in a quadrant.

Building on their previous work on plasmonic sensing, their results show that it is possible to independently and simultaneously measure local changes in refractive index for all four sensors with a quantum advantage. This allows sensors to be probed at the same time rather than in series or sequentially, which is necessary for research such as dark matter detection or imaging applications. The research led to a quantum improvement in the sensitivity of the four sensors, between 22 and 24% compared to the corresponding classical configuration.

“Typically you use having correlations over time and taking advantage of noise levels below the classical limit, i.e. compression, to improve a measurement and get quantum improvement,” said ORNL researcher Alberto Marino. “In this case, we combined temporal and spatial correlations to probe multiple sensors at the same time and achieve simultaneous quantum enhancement for each of them.”

Marino, who is group leader for quantum sensing and computing at ORNL and is named a joint professor at the University of Oklahoma, added that the goal of this research was to extract much more information of a system while maintaining a quantum advantage.

One area where this will be used in practice by the lab is the detection of dark matter, which scientists believe is the unexplained matter that extends across the universe. This type of matter does not interact with light, but exerts a gravitational force. Detecting dark matter therefore requires large sensor networks due to its weak interaction with standard matter.

“We now have a project where we are doing dark matter detection that will require a set of sensors,” Marino said. “Our work on parallel quantum sensing will play an important role in this because it is a first step toward probing multiple sensors simultaneously and will allow us to go beyond our current work with a single optomechanical sensor.”

For dark matter detection, the ORNL team is currently using quantum states of light to improve the sensitivity of an optomechanical sensor based on micro-electromechanical systems, or MEMS. Light is used to measure the acceleration imparted to MEMS due to its expected interaction with dark matter. In the future, the source will be optimized to contain as many independently quantum correlated regions, or coherence zones, as possible. Each of these coherence zones will then be used to probe a sensor in the network.

“For example, the combination of parallel quantum sensing sensors and plasmonic sensors could improve the detection of multiple pathogens in the blood at the same time, by allowing each sensor in an array to detect a different thing,” Marino said.