Heterodyne sensing of microwaves with a quantum sensor

Area of Science:

• Quantum sensing
• Optics and photonics
• Solid-state physics

Background:

• Diamond quantum sensors detect weak microwave magnetic fields.
• Spectral resolution is limited by sensor lifetime in current protocols.

Purpose of the Study:

• To demonstrate a heterodyne detection method for microwaves (MW).
• To achieve lifetime-independent spectral resolution in the GHz range.
• To explore control over MW-field interactions with two-level systems.

Main Methods:

• Utilized a heterodyne detection method referencing MW signals to a local oscillator.
• Generated initial superposition states from a coherent source.
• Applied dressing fields, pulsed Mollow absorption, and Floquet dynamics for control.

Main Results:

• Achieved spectral resolution below 1 Hz for a 4 GHz signal, far below the kilohertz sensor lifetime limit.
• Demonstrated control over MW-field interactions via dressing fields.
• Showcased pulsed Mollow absorption for improved sensitivity and Floquet dynamics for robust, frequency-independent control.

Conclusions:

• The heterodyne method provides lifetime-independent spectral resolution for MW sensing.
• Advanced control techniques offer enhanced sensitivity and robustness in quantum sensing applications.
• This work is vital for future studies in high-resolution sensing of weak microwave signals across a broad frequency range.