Quantum sensors

Spin-based magnetometers detect magnetic fields by measuring the spin properties of particles. In NV-based magnetometers, for example, the spin’s energy levels split in an external magnetic field, causing a change in the NV center’s optical properties, such as its fluorescence intensity or polarization. By monitoring these optical properties, the strength and direction of the magnetic field can be inferred. These sensors can detect extremely weak magnetic fields down to the level of single electron spins. Moreover, NV centers exhibit remarkable stability and can operate at room temperature, making them highly practical for various applications.

Application

A quantum Hall effect (QHE) sensor is a device that utilizes the quantum.
In a quantum Hall effect (QHE) sensor, a two-dimensional electron gas (2DEG) is typically confined within a semiconductor material, such as gallium arsenide (GaAs), and cooled to low temperatures. Under certain conditions, the Hall resistance (the voltage across the material perpendicular to the current flow divided by the current) becomes quantized, which allows precise measurements of the magnetic field by determining the Hall resistance and knowing the geometry of the device. QHE sensors are known for their high sensitivity, accuracy, and stability, making them valuable tools for applications such as metrology, magnetic field mapping, and fundamental research in condensed matter physics. Efforts are ongoing to develop QHE sensors that can operate at higher temperatures, thus increasing their practicality for various applications.

Application

An Atomic Force Microscope (AFM) tip can be considered a quantum sensor due to the fundamental principles governing its operation. It involves the interaction between the tip and the sample at the nanoscale level, where quantum effects become significant. These effects include van der Waals forces, tunneling, and atomic interactions. Nanofabrication methods enable the precise control of dimensions and shapes at the nanometer scale, which is crucial for producing AFM tips with the desired characteristics. For example, FIB milling can be used to fabricate AFM tips directly on the substrate or to shape pre-fabricated tips.

Application pattern

Optical quantum sensors exploit the quantum properties of light for highly sensitive measurements. They utilize phenomena like quantum interference, single-photon detection, and entanglement to achieve superior performance. These sensors can detect individual photons and utilize entanglement for correlated measurements. Quantum metrology techniques enable precise measurements beyond classical limits, with applications in fields such as navigation and fundamental physics. Quantum imaging methods enhance resolution and sensitivity, even in challenging environments like scattering media. Overall, optical quantum sensors offer groundbreaking potential for scientific research and practical applications.