Physics

Superheterodyne receiver

Noise (video)

Image (mathematics)

Rydberg atom

Optics

Quantum noise

Engineering

Atomic physics

Artificial intelligence

Photon

Quantum simulator

Atomic clock

Ionization

Sensitivity (control systems)

Electronic engineering

Microwave

Computer science

Quantum computer

Quantum mechanics

Electric field

Rydberg formula

Quantum

Quantum sensor

Nature Physics

Highly sensitive phase- and frequency-resolved detection of microwave electric fields is of central importance in a wide range of fields, including cosmology1,2, meteorology3, communication4 and microwave quantum technology5. Atom-based electrometers6,7 promise traceable standards for microwave electrometry, but their best sensitivity is currently limited to a few μV cm−1 Hz−1/2 (refs. 8,9) and they only yield information about the field amplitude and polarization10. Here, we demonstrate a conceptually new microwave electric field sensor—the Rydberg-atom superheterodyne receiver (superhet). The sensitivity of this technique scales favourably, achieving even 55 nV cm−1 Hz−1/2 with a modest set-up. The minimum detectable field of 780 pV cm−1 is three orders of magnitude smaller than what can be reached by existing atomic electrometers. The Rydberg-atom superhet allows SI-traceable measurements, reaching uncertainty levels of 10−8 V cm−1 when measuring a sub-μV cm−1 field, which has been inaccessible so far with atomic sensors. Our method also enables phase and frequency detection. In sensing Doppler frequencies, sub-μHz precision is reached for fields of a few hundred nV cm−1. This work is a first step towards realizing electromagnetic-wave quantum sensors with quantum projection noise-limited sensitivity. Such a device will impact diverse areas like radio astronomy, radar technology and metrology. The Rydberg-atom superhet, based on microwave-dressed Rydberg atoms and a tailored electromagnetically induced transparency spectrum, allows SI-traceable measurements of microwave electric fields with unprecedented sensitivity.

Atomic superheterodyne receiver based on microwave-dressed Rydberg spectroscopy