Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2025 Dec 12;16:2448. doi: 10.1038/s41598-025-32361-8

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© The Author(s) 2025

Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.

PMC Copyright notice

Fig. 2 — Characterization of noise reduction and stability enhancement via signal-idler correlation. (a) shows the raw histograms of photon arrival times from the signal and idler detectors at 2950 nm. A 150 ns gating window (black dashed lines) is applied to both channels to suppress background noise. Arrival times are recorded on a time tagger relative to a trigger signal derived from the pulsed laser. (b) Correlation between detected counts in the signal and idler arms at 3000 nm, with a linear fit (black dashed line) (c) Standard deviation of idler counts before (orange) and after (purple) normalization using signal-idler correlation. Improvement is observed at wavelengths where fluctuations significantly exceed the shot noise level (black dashed line). (d) Histogram of idler counts before and after normalization at 3000 nm. The full width at half maximum (FWHM) is reduced after applying correlation-based rescaling, indicating enhanced stability.