Amplified quantum nondemolition measurements of optical quadratures using quadratic nonlinearity
Phys. Rev. A 113, 033729 – Published 23 March, 2026
DOI: https://doi.org/10.1103/v27s-l2r4
Abstract
We propose the concept of amplified quantum nondemolition measurement of a quadrature amplitude of optical field. Similarly to standard quantum nondemolition measurement, it does not introduce a backaction noise into the measured quadrature. At the same time, it provides a noiseless amplification of this quadrature. We propose a possible practical implementation of this concept based on the nondegenerate optical parametric amplifier. We show that, assuming demanding but realistic values of the optical squeezing and losses, a sensitivity several times better than the standard quantum limit can be achieved.
