Excess-noise suppression for a squeezed state propagating through random amplifying media via wave-front shaping

TL;DR

This paper presents a wavefront shaping method to suppress excess quantum noise in squeezed states passing through random amplifying media, enabling noise reduction beyond the shot-noise limit for quantum information applications.

Contribution

The study introduces a novel wavefront shaping technique to effectively reduce quantum noise in squeezed states after propagation through complex media, surpassing traditional noise limits.

Findings

Average output quantum noise can be suppressed beyond the shot-noise limit.

Both lower amplification and higher input squeezing improve noise suppression.

Demonstrates feasibility for quantum information processing in complex environments.

Abstract

After propagating through a random amplifying medium, a squeezed state commonly shows excess noise above the shot-noise level. Since large noise can significantly reduce the signal-to-noise ratio, it is detrimental for precision measurement. To circumvent this problem, we propose a noise-reduction scheme using wavefront shaping. It is demonstrated that the average output quantum noise can be effectively suppressed even beyond the shot-noise limit. Both the decrease on amplification strength and the increase on input squeezing strength can give rise to a decrease in the suppressed average quantum noise. Our results not only show the feasibility of manipulating the output quantum noise of random amplifying media, but also indicate potential applications in quantum information processing in complex environments, such as, quantum imaging, quantum communication, and quantum key distribution.