aqora

Harnessing nonlinearity for linear measurements

Hendrik Bluhm

Researchers develop a new type of superconducting quantum interference device (SQUID) with significantly enhanced sensitivity and bandwidth, which can function as a general-purpose magnetic sensor.

PhysicsApr 4, 20111 citation

Out of the loop—a superconducting tunnel junction that behaves like a SQUID

Edward J. Romans

Recently there has been a trend to develop nanoscale superconducting quantum interference devices (nanoSQUIDs) with the aim to reach magnetic flux sensitivities sufficient to detect the flip of a single electron spin in close proximity (see refs [1], [2]

Superconductor Science and TechnologyApr 27, 20181 citation

A High Sensitivity Closed-Loop Spin-Exchange Relaxation-Free Atomic Magnetometer With Broad Bandwidth

Qingqian Guo, Tao Hu, Chun-qiao Chen +6 more

Spin-exchange relaxation-free (SERF) atomic magnetometers are the promising non-cryogenic sensors to potentially replace the superconducting quantum interference device (SQUID) in the ultra-weak magnetic-field measurements. Although the SERF magnetometers have achieved a sensitivity of sub-femtotesla, the bandwidth is limited at a narrow range. In this work, we developed a closed-loop SERF magnetometer under proportional-integral (PI) control, the bandwidth could be adaptively tuned and extended above 1.2 kHz. A nearly 40-fold enhancement of the typical bandwidth was achieved in comparison with the open-loop system and the sensitivity was maintained at 15 fT/Hz1/2from 30 Hz to 750 Hz. Moreover, the magnetic field dynamic range could also be greatly improved. This proposed atomic magnetometer with higher bandwidth, sensitivity, and dynamic range has a good prospect in developing a compact, portable, and non-cryogenic magnetic field sensor and may find more applications in biomedical, nuclear magnetic resonance, and fundamental physics research.Spin-exchange relaxation-free (SERF) atomic magnetometers are the promising non-cryogenic sensors to potentially replace the superconducting quantum interference device (SQUID) in the ultra-weak magnetic-field measurements. Although the SERF magnetometers have achieved a sensitivity of sub-femtotesla, the bandwidth is limited at a narrow range. In this work, we developed a closed-loop SERF magnetometer under proportional-integral (PI) control, the bandwidth could be adaptively tuned and extended above 1.2 kHz. A nearly 40-fold enhancement of the typical bandwidth was achieved in comparison with the open-loop system and the sensitivity was maintained at 15 fT/Hz1/2from 30 Hz to 750 Hz. Moreover, the magnetic field dynamic range could also be greatly improved. This proposed atomic magnetometer with higher bandwidth, sensitivity, and dynamic range has a good prospect in developing a compact, portable, and non-cryogenic magnetic field sensor and may find more applications in biomedical, nuclear magnetic resonance, and fundamental physics research.

IEEE Sensors JournalAug 3, 202136 citations

New Atomic Magnetometer Achieves Subfemtotesla Sensitivity

Richard Fitzgerald

In a field dominated by superconducting quantum interference devices (SQUIDs), a rival technique has gotten a boost by operating in a new parameter regime.

Physics TodayJul 1, 200310 citations

Quantum Sensors and Metrology: Principles and Technological Developments

Celestine Usmonov

Quantum sensors and metrology harness quantum phenomena—such as superposition, entanglement, and squeezing—to achieve precision measurements beyond classical limits. This review presents an overview of the fundamental principles underlying quantum sensing, including quantum coherence, entanglement-assisted measurement, and quantum-enhanced interferometry. Various quantum sensor platforms are discussed, including atomic clocks, nitrogen-vacancy (NV) center magnetometers, superconducting quantum interference devices (SQUIDs), optomechanical sensors, and trapped-ion systems. We explore their operational mechanisms, performance metrics, and technological implementations. Comparative analyses highlight sensitivity, spatial resolution, bandwidth, and environmental robustness. Advances in materials, control techniques, and hybrid architectures are examined, and emerging applications in navigation, geophysics, medical imaging, and fundamental physics are reviewed. Finally, future prospects for scalable and robust quantum metrology are discussed.Quantum sensors and metrology harness quantum phenomena—such as superposition, entanglement, and squeezing—to achieve precision measurements beyond classical limits. This review presents an overview of the fundamental principles underlying quantum sensing, including quantum coherence, entanglement-assisted measurement, and quantum-enhanced interferometry. Various quantum sensor platforms are discussed, including atomic clocks, nitrogen-vacancy (NV) center magnetometers, superconducting quantum interference devices (SQUIDs), optomechanical sensors, and trapped-ion systems. We explore their operational mechanisms, performance metrics, and technological implementations. Comparative analyses highlight sensitivity, spatial resolution, bandwidth, and environmental robustness. Advances in materials, control techniques, and hybrid architectures are examined, and emerging applications in navigation, geophysics, medical imaging, and fundamental physics are reviewed. Finally, future prospects for scalable and robust quantum metrology are discussed.

Advance Physics LetterFeb 26, 20220 citations

SQUID: Superconducting Quantum Interference Device

Werner R.G. Buckel

Physikalische BlätterOct 1, 19835 citations

Viewpoint: Harnessing nonlinearity for linear measurements

Abstract

Related papers

Viewpoint: Harnessing nonlinearity for linear measurements

Abstract

Related papers