Quantum light squeezes the noise out of microscopy signals

Phys.org  September 8, 2020
A team of researchers in the US (Tulane University, MIT, University of Colorado) demonstrated the first practical application of nonlinear interferometry by measuring the displacement of an atomic force microscope microcantilever with quantum noise reduction of up to 3 dB below the standard quantum limit, corresponding to a quantum-enhanced measurement of beam displacement. They minimized photon backaction noise while taking advantage of quantum noise reduction by transducing the cantilever displacement signal with a weak squeezed state while using dual homodyne detection with a higher power local oscillator. This approach may enable quantum-enhanced broadband, high-speed scanning probe microscopy…read more. TECHNICAL ARTICLE 

ORNL researchers developed a quantum, or squeezed, light approach for atomic force microscopy that enables measurement of signals otherwise buried by noise. Credit: Raphael Pooser, ORNL, U.S. Dept. of Energy