Quantum limits in the measurement of very small displacements in optical images

TL;DR

This paper investigates the quantum limits of measuring tiny displacements in optical images and proposes multimode nonclassical light states to surpass the standard quantum limit, enhancing measurement resolution.

Contribution

It introduces multimode nonclassical states of light that can significantly improve displacement measurement resolution beyond the standard quantum limit.

Findings

Standard quantum limit cannot be surpassed with single-mode squeezed light.

Multimode nonclassical states enable orders-of-magnitude resolution enhancement.

Theoretical framework for generating and using these states is provided.

Abstract

We consider the problem of the measurement of very small displacements in the transverse plane of an optical image with a split photodetector. We show that the standard quantum limit for such a measurement, which is equal to the diffraction limit divided by the square root of the number of photons used in the measurement, cannot be overcome by use of ordinary single-mode squeezed light. We give the form of possible multimode nonclassical states of light, enabling us to enhance by orders of magnitude the resolution of such a measurement beyond the standard quantum limit.