Quantum Sensing Overview

Quantum sensing exploits the strong coupling of quantum systems to its environment to detect and measure physical quantities with extraordinary precision, far surpassing what is achievable with classical approaches. Following the definitions of Degen et al 2017, quantum sensors can be categorized into three main types based on their operating principles.

Quantum object sensors utilizing the interaction between discrete quantum states and external physical quantities such as magnetic or electric fields to detect changes with high sensitivity. 

Quantum coherence sensors relying on maintaining and manipulating coherent superpositions of quantum states, using the accumulation of phase information to reveal subtle signal variations. 

Entanglement-enhanced sensors employ entangled quantum states to achieve sensitivities that exceed the classical limit, unlocking new possibilities for measuring phenomena with remarkable accuracy. 

Across all three modalities of quantum sensing, Zurich Instruments provides tools that deliver precision signal generation, low-noise readout, and synchronized control  - enabling scientists to accelerate discoveries in quantum sensing.

We support key quantum sensing technologies:

• NV center-based sensors
• Optically pumped magnetometers (OPMs)
• SQUID-based sensors
• Tunneling magnetoresistance (TMR) sensors
• Quantum Hall effect
• Trapped ion sensors

Each quantum sensing technology benefits from Zurich Instruments’ unique capabilities in lock-in amplifiers, quantum analyzers and signal generators.

NV Center Magnetometry

NV centers in diamond are a robust platform for sensing in challenging environments, offering versatile sensing capabilities, ranging from biological and nanoscale magnetic imaging to quantum-enhanced navigation systems. Zurich Instruments provides tools tailored to both ensemble and single-NV sensing.

Ensemble NV sensing involves detecting the collective optical response of many NV centers, often in pulsed configurations. The MFLI Lock-in Amplifier excels at extracting these signals with high signal-to-noise ratios, thanks to its low input noise and kHz–MHz demodulation bandwidths.

Single NV sensing, such as scanning probe magnetometry, demand synchronized laser and microwave pulse control. Our HDAWG Arbitrary Waveform Generator delivers sample-precise pulse sequences, while LabOne Q simplifies the orchestration of complex experiments. 

Optically Pumped Magnetometers 

Optically pumped magnetometers (OPMs) are cryogen-free quantum sensors based on alkali vapors, capable of detecting femtotesla-level fields. Zurich Instruments provides solutions for two distinct application areas:

Life Sciences - Magnetoencephalography (MEG), magnetocardiography (MCG), and low-field MRI require modulation frequencies in the kHz–MHz range and ultra-low readout noise.

Quantum Navigation -  Assured positioning, navigation and timing (A-PNT) rely on scalable multi-sensor setups and real-time processing in a compact, field-deployable systems.

The MFLI Lock-in Amplifier meets these needs with demodulation bandwidths up to 5 MHz, low-noise readout, and integrated PID controllers for feedback stabilization.

SQUID-Based Systems

SQUID sensors rely on quantum mechanical phenomena such as the Josephson effect to detect very weak magnetic signals. They are used for applications ranging from biological and magnetic imaging to magnetic and graviometric navigation systems.

The MFLI and UHFLI Lock-in Amplifiers provide wide-bandwidth post-amplification signal demodulation.

• Real-time analysis tools such as spectrum analyzers and sweeper modules help track small signals over long time windows.
• Synchronization with external hardware is supported through flexible trigger and marker I/O.

Read more about the MFLI for SQUID characterisation.

Tunneling Magnetoresistance (TMR)

TMR sensors exploit the change in electrical resistance of magnetic tunnel junction in the presence of magnetic field.  This measurable change in resistance, enabling precise detection of magnetic properties, including field strength (picotesla levels), position, and direction. Applications range from lab-on-chip NMR to portable magnetic anomaly detectors. TMR signals, typically modulated in the kHz–MHz range, are ideally suited for Zurich Instruments’ lock-in amplifiers.

The MFLI enables low-noise signal demodulation, while integrated signal generation capabilities drive sensor modulation with precision.

Read how our users benefit from the MFLI for TMR.