Fisher information analysis on quantum-enhanced parameter estimation in electromagnetically-induced-transparency spectrum with single photons

TL;DR

This paper analyzes the spectral lineshape measurement in EIT media using Fisher information, comparing single-photon and coherent probes to understand quantum advantages in quantum sensing.

Contribution

It provides a systematic Fisher information analysis of single-photon EIT spectra, revealing quantum advantages and spectral classification into EIT and ATS regimes.

Findings

Single-photon probes offer quantum advantage in spectral measurement.

Fisher information analysis distinguishes EIT and ATS regimes.

Systematic understanding of quantum sensing with EIT spectra.

Abstract

Electromagnetically-induced-transparency (EIT) spectroscopy has been used as a sensitive sensor in quantum metrology applications. The sensitivity of a sensor strongly depends on the measurement precision of EIT spectrum. In this work, we present a theoretical study of the spectral lineshape measurement on a three-level $\Lambda$-type EIT media based on Fisher information (FI) analysis. Using two kinds of probing source: the single-photon Fock state and the coherent state, we calculate the FI in an EIT medium and quantify the quantum advantage and limitations of the single-photon probe. The analysis of FI structure also provides a clear picture to classify the spectral lineshape into two different regimes, the EIT and Aulter-Townes splitting (ATS). This work provides a systematic analysis of the single-photon EIT spectrum, which provides essential knowledge of quantum sensing based on EIT and deepens our understanding of spectral characteristics of $\Lambda$-type media.