High precision Optical AC Magnetometry using Dynamical Decoupling

TL;DR

This paper introduces a high-precision optical AC magnetometer using a Terbium-doped fiber with dynamical decoupling, significantly enhancing sensitivity by preserving photon states against noise.

Contribution

It demonstrates the application of dynamical decoupling in optical fiber magnetometry to improve sensitivity and bandwidth for AC magnetic field detection.

Findings

Enhanced sensitivity achieved through dynamical decoupling.

Minimum detectable field inversely proportional to fiber length.

Effective noise reduction despite pulse timing errors.

Abstract

We propose a magnetometer for the precise measurement of AC magnetic fields that uses a Terbium-doped optical fiber with half-waveplates built into it at specified distances. Our scheme uses an open-loop quantum control technique called dynamical decoupling to reduce the noise floor and thus increase the sensitivity. We show that dynamical decoupling is extremely effective in preserving the photon state evolution due to the external AC magnetic field from random birefringence in the fiber, even when accounting for errors in pulse timing. Hence we achieve high sensitivity. For a given inter-waveplate distance, the minimum detectable field is inversely proportional to fiber length, as is the bandwidth of detectable frequencies.