Quantum Fluctuations in Nonlinear Optics

TLDR: In this article, the effect of quantum fluctuations on optical detection systems such as the Michelson interferometer was investigated and it was shown that quantum fluctuations may affect the final measurement in two ways; namely photon counting fluctuations and radiation pressure fluctuations.

Abstract: An ultimate limit to the sensitivity achieved by detectors for gravitational radiation is set by quantum fluctuations. All detection systems are subject to this limit, however we shall restrict our attention to the affect of quantum fluctuations on optical detection systems such as the Michelson interferometer. The techniques developed to treat quantum fluctuations in optical systems may prove to be useful in analysing other detection systems. In a Michelson interferometer quantum fluctuations may affect the final measurement in two ways; namely photon counting fluctuations and radiation pressure fluctuations. The effect of these sources of error oil the interferometer detection scheme have been discussed by Caves and by Unruh. Caves suggested that these errors could be reduced by injecting special states of the radiation field with reduced fluctuations into one port of the interferometer. These states called “squeezed states” show reduced fluctuations in one quadrature and enhanced fluctuations in the other4–8. They also play a general role in quantum non demolition (Q.N.D.) measurements9 since the state of a system after certain Q.N.D. measurements (back action evading measurements) resembles a squeezed state.