QUTEMAG · Quantum-Enhanced Optical Magnetometers

Quantum-Enhanced Optical Magnetometers

Optical magnetometers, implemented by optical interrogation of alkali atoms contained in a vapour cell, are among the most sensitive detectors of magnetic fields. By operating at large atomic densities and low magnetic fields, in a regime often referred to as Spin-Exchange Relaxation-Free (SERF), these devices reach record-level sensitivities enabling the measurement of very weak magnetic signals originating from a wide variety of sources in applications ranging from navigation to magnetocardiography. Their recent miniaturization has opened attractive perspectives for their deployment in applications such as non-invasive bio-magnetic imaging of the brain, attitude control in space based missions, and non-destructive testing for manufacturing, and even wearable devices for personalized health-care diagnosis. To fully unleash their potential in real world applications a number of open fundamental and technological challenges need to be addressed. One fundamental problem is quantum noise, which limits the best attainable sensitivity δB of these devices to scale with sensor volume V as δB ~ V-1/2. For this reason, the sensitivity of these devices degrades as they are further miniaturized. Moreover, to reach their highest sensitivity optical magnetometers sacrifice temporal resolution; as a result, fast-varying signals have remained outside their reach. A promising approach to overcome these limitations relies on Quantum Optics tools, such as quantum-non-demolition (QND) measurements and squeezed light that allow ultra-sensitive measurements, increased device bandwidth, and the enhancement of physical systems beyond their classical limits. To date, in a proof-of-principle way, QND and squeezed light have been used to improve the performance of optical magnetometers independently but not within the same device. Their simultaneous use remains an open challenge. The overall objective of the project Quantum-Enhanced Optical Magnetometers QUTEMAG was to combine QND and squeezed light to magnetometry at large atomic densities in a regime where spin-exchange collisions dominate the spin dynamics. This regime is of particular interest for the implementation of high-sensitivity, miniaturized, and high-bandwidth magnetometers as described above. The tools developed during QUTEMAG will find application to enhance current technology most suitable to address challenges in the real world.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз