Shot-noise-limited magnetometer with sub-picotesla sensitivity at room temperature

Area of Science:

• Atomic physics
• Quantum optics
• Sensor technology

Background:

• Atomic magnetometers offer high sensitivity for magnetic field measurements.
• Achieving photon shot-noise-limited (SNL) performance is crucial for pushing sensitivity boundaries.
• Room-temperature operation simplifies instrumentation and broadens applicability.

Purpose of the Study:

• To develop and characterize a room-temperature optical magnetometer operating at the photon shot-noise limit.
• To demonstrate high sensitivity in a practical atomic sensor configuration.
• To explore the potential for integrating squeezed light for enhanced quantum sensing.

Main Methods:

• Utilized amplitude modulated optical rotation in an 85Rb vapor cell.
• Employed an anti-relaxation coating to preserve atomic coherence.
• Measured magnetic field sensitivity at room temperature.

Main Results:

• Achieved a sensitivity of 70 fT/√Hz at 7.6 μT.
• Confirmed photon shot-noise-limited (SNL) behavior across a range of magnetic fields (5-75 μT).
• Demonstrated noise scaling consistent with theoretical SNL predictions.

Conclusions:

• The developed optical magnetometer operates at the photon shot-noise limit.
• The instrument exhibits best-in-class sensitivity at room temperature.
• This system is a strong candidate for utilizing squeezed light in state-of-the-art atomic sensors.