Generation of Optical Coherent State Superpositions by Number-Resolved Photon Subtraction from Squeezed Vacuum

TL;DR

This paper demonstrates the generation of optical coherent state superpositions by subtracting up to three photons from squeezed vacuum light, utilizing a high-efficiency photon-number-resolving detector to confirm the creation of larger-amplitude CSSs.

Contribution

First experiment to use full photon-number-resolving capabilities of a transition edge sensor for CSS generation via photon subtraction from squeezed vacuum.

Findings

Successfully created CSS with mean photon number 2.75

Achieved fidelity of 0.59 with ideal CSS

Higher photon subtraction yields larger-amplitude CSSs

Abstract

We have created heralded coherent state superpositions (CSS), by subtracting up to three photons from a pulse of squeezed vacuum light. To produce such CSSs at a sufficient rate, we used our high-efficiency photon-number-resolving transition edge sensor to detect the subtracted photons. This is the first experiment enabled by and utilizing the full photon-number-resolving capabilities of this detector. The CSS produced by three-photon subtraction had a mean photon number of 2.75 -0.24/+0.06 and a fidelity of 0.59 -0.14/+0.04 with an ideal CSS. This confirms that subtracting more photons results in higher-amplitude CSSs.