Extreme Amplification in Ultrasensitive Interferometric Phase Metrology

Fundamental and practical disciplines, ranging from gravitational wave detection to assisted manufacturing, require highly precise length measurements, often at the sub-nanometer scale. Optical interferometry is the backbone of most methods, as it facilitates access to the nanometer domain, particularly when combined with advanced algorithms and phase detection systems, which go beyond simple fringe counting. By definition, phase measurements rely on a reference, giving rise to a variety of interferometric techniques such as quadrature detection, spatial carrier interferometry, and heterodyne interferometry.