Oak Ridge National Labs (ORNL) has quantum sensors that use a “squeezed” state of light to greatly reduce statistical noise that occurs in ordinary light. This could impact a wide range of potential applications from airport security scanning to gravitational wave measurements.
Above – ACS Photonics. Copyright 2019. American Chemical Society.
“Quantum-enhanced microscopes are particularly exciting,” ORNL’s Ben Lawrie said. “These quantum sensors can ‘squeeze’ the uncertainty in optical measurements, reducing the uncertainty in one variable while increasing the uncertainty elsewhere.” Squeezed light refers to a quantum state where the statistical noise that occurs in ordinary light is greatly reduced. Squeezed atomic force microscopes, or AFMs, could operate hundreds of times faster than current microscopes while providing a nanoscale description of high-speed electronic interactions in materials. This enhancement is enabled by removing a requirement in most AFMs that the microscope operate at a single frequency. Future sensing technologies that harness quantum properties could be deployed as new quantum-enabled devices or as “plug-ins” for existing sensors.
The minimum resolvable signal in sensing and metrology platforms that rely on optical readout fields is increasingly constrained by the standard quantum limit, which is determined by the sum of photon shot noise and back-action noise. A combination of back-action and shot noise reduction techniques will be critical to the development of the next generation of sensors for applications ranging from high-energy physics to biochemistry and for novel microscopy platforms capable of resolving material properties that were previously obscured by quantum noise. This Perspective reviews the dramatic advances made in the use of squeezed light for sub-shot-noise quantum sensing in recent years and highlights emerging applications that enable new science based on signals that would otherwise be obscured by noise at the standard quantum limit.