One of the many counterintuitive and bizarre insights of quantum mechanics is that even in a vacuum—what many of us think of as an empty void—all is not completely still. Low levels of noise, known as quantum fluctuations, are always present. Always, that is, unless you can pull off a quantum trick. And that’s just what a team led by researchers at the California Institute of Technology (Caltech) has done. The group has engineered a miniature silicon system that produces a type of light that is quieter at certain frequencies—meaning it has fewer quantum fluctuations—than what is usually present in a vacuum.
SEM image of the silicon micromechanical resonator used to generate squeezed light. Light is coupled into the device using a narrow waveguide and reflects off a back mirror formed by a linear array of etched holes. Upon reflection, the light interacts with a pair of double-nanobeams (micromechanical resonator/optical cavity), which are deflected in a way that tends to cancel fluctuations in the light. (b) Numerical model of the differential in-plane motion of the nanobeams.
Credit: Caltech/Amir Safavi-Naeini, Simon Groeblacher, and Jeff Hill