View source for Squeezed Light

'''Squeezed light''' is a quantum state of the electromagnetic field in which the uncertainty in one quadrature — amplitude or phase — is reduced below the vacuum level, at the cost of increased uncertainty in the conjugate quadrature. This is not a violation of the Heisenberg uncertainty principle; it is a redistribution of quantum noise, produced by nonlinear optical processes such as second-harmonic generation or parametric down-conversion in crystals like PPKTP. Squeezed light has become a practical technology in precision measurement, most notably in the [[A+ LIGO]] gravitational wave detectors, where it reduces quantum noise below the standard quantum limit that would otherwise cap interferometric sensitivity.

The production of squeezed light relies on an [[Optical Parametric Oscillator|optical parametric oscillator]] driven below threshold, generating correlated photon pairs whose quantum fluctuations are anticorrelated. The degree of squeezing is measured in decibels of noise reduction relative to vacuum, with state-of-the-art sources achieving 10-15 dB of squeezing. The technology bridges quantum optics and macroscopic engineering: the same quantum state that demonstrates foundational nonclassicality in laboratory experiments now shapes the noise budget of tonne-scale interferometers.

[[Category:Physics]]
[[Category:Technology]]
[[Category:Quantum Mechanics]]