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We demonstrate a method for broadband tunable continuous frequency electric field measurement based on the DC Stark effect in Rydberg atoms. In our experiment, we place a pair of parallel electrode plates inside the atomic vapor cell, utilizing the DC Stark effect to induce splitting and shifting of the Rydberg energy levels, thereby altering the resonance frequency of the Stark subpeaks. By employing the 52D5/2 Rydberg state, we achieve electric field measurements in the frequency range of 5.083–14.470 GHz. At an EDC of 3.45 V/cm and a resonant microwave frequency of 14.470 GHz, using heterodyne technology, the microwave electric field sensitivity is 538.89 μV/cm/√Hz, with a linear dynamic range of 23 dB. In comparison, a Rydberg heterodyne receiver with an EDC of 0 V/cm and a resonant microwave frequency of 5.083 GHz has a sensitivity of 5.43 μV/cm/√Hz and a linear dynamic range of 51 dB. This work will promote the study of atomic microwave receivers in continuous microwave frequency measurement. [ABSTRACT FROM AUTHOR]

We demonstrate a continuously tunable electric field measurement based on the far off-resonant AC stark effect in a Rydberg atomic vapor cell. In this configuration, a strong far off-resonant field, denoted as a local oscillator (LO) field, acts as a gain to shift the Rydberg level to a high sensitivity region. An incident weak signal field with a few hundreds of kHz difference from the LO field is mixed with the LO field in the Rydberg system to generate an intermediate frequency signal, which is read out by Rydberg electromagnetically induced transparency (Rydberg-EIT) spectroscopy. Not like resonant EIT-Autler–Townes spectra, we realize the electric field measurement of the signal frequency from 2 to 5 GHz using a single Rydberg state. The detectable field strength is down to 2.25 μV/cm with sensitivity of the electrometry 712 nV cm−1 Hz−1/2, and a linear dynamic range is over 65 dB. The detectable field strength is comparable with a resonant microwave-dressed Rydberg heterodyne receiver using the same system, which is 0.96 μV/cm with sensitivity of 304 nV cm–1 Hz−1/2. We also show the system has an inherent polarization selectivity feature. Our method can provide high sensitivity of electric field measurement and be extended to arbitrary frequency measurements. [ABSTRACT FROM AUTHOR]

Rydberg atoms have been shown to be very useful in performing absolute measurements of the magnitude of a radio frequency (RF) field using electromagnetically induced transparency. However, there has been less success in using Rydberg atoms for the measurement of the phase of an RF field. Measuring the phase of a RF field is a necessary component for many important applications, including antenna metrology, communications, and radar. We demonstrate a scheme for measuring the phase of an RF field by using Rydberg atoms as a mixer to down-convert an RF field at 20 GHz to an intermediate frequency on the order of kHz. The phase of the intermediate frequency corresponds directly to the phase of the RF field. We use this approach to measure the phase shift on an electromagnetic wave from a horn antenna as the antenna is placed at different distances from the Rydberg atom sensor. The atom-based RF phase measurements allow us to measure the propagation constant of the RF wave to within 0.1% of the theoretical value. [ABSTRACT FROM AUTHOR]

We present a technique for measuring radio-frequency (RF) electric field strengths with sub-wavelength resolution. We use Rydberg states of rubidium atoms to probe the RF field. The RF field causes an energy splitting of the Rydberg states via the Autler-Townes effect, and we detect the splitting via electromagnetically induced transparency (EIT). We use this technique to measure the electric field distribution inside a glass cylinder with applied RF fields at 17.04 GHz and 104.77 GHz. We achieve a spatial resolution of ≈100 μm, limited by the widths of the laser beams utilized for the EIT spectroscopy. We numerically simulate the fields in the glass cylinder and find good agreement with the measured fields. Our results suggest that this technique could be applied to image fields on a small spatial scale over a large range of frequencies, up into the sub-terahertz regime. [ABSTRACT FROM AUTHOR]