The electric field sensing technology based on the Rydberg atom has attracted widespread attention due to its powerful detection ability for the amplitude, phase, and polarization of the electric field. In this work, based on the electromagnetically induced transparency (EIT) of the Rydberg atom and combined with a heterodyne Rydberg atom-based mixer, we measured the binary array composed of the Rydberg Field Probes (RFPs). The measured phase difference of the electric field at two different RFPs is related to the direction of incidence. We digitally transform the received signal at 2.63 GHz and conduct digital beamforming (DBF) processing to obtain its array pattern and beam direction. The measurement accuracy and reliability are greatly improved compared with the phase comparison method, and the angle-of-arrival (AOA) variance is less than 1.5°. The effectiveness of DBF based on the Rydberg atomic sensor is verified, which lays the foundation for the subsequent linear and planar array reception of the Rydberg atomic sensor. In addition, the occlusion based on RFPs is also measured, and its weak occlusion characteristics are confirmed. This unique feature provides feasible support for the 3-D receiving array based on the Rydberg atomic sensor.
The electric field sensing technology based on the Rydberg atom has attracted widespread attention due to its powerful detection ability for the amplitude, phase, and polarization of the electric field. In this work, based on the electromagnetically induced transparency (EIT) of the Rydberg atom and combined with a heterodyne Rydberg atom-based mixer, we measured the binary array composed of the Rydberg Field Probes (RFPs). The measured phase difference of the electric field at two different RFPs is related to the direction of incidence. We digitally transform the received signal at 2.63 GHz and conduct digital beamforming (DBF) processing to obtain its array pattern and beam direction. The measurement accuracy and reliability are greatly improved compared with the phase comparison method, and the angle-of-arrival (AOA) variance is less than 1.5°. The effectiveness of DBF based on the Rydberg atomic sensor is verified, which lays the foundation for the subsequent linear and planar array reception of the Rydberg atomic sensor. In addition, the occlusion based on RFPs is also measured, and its weak occlusion characteristics are confirmed. This unique feature provides feasible support for the 3-D receiving array based on the Rydberg atomic sensor.
Doppler frequency shift (DFS) and angle of arrival (AOA) measurements play a crucial role in modern radar, aviation, and satellite communication systems. Rydberg atom-based receivers are renowned for the high sensitivity, wide operating frequency range, and immunity to electromagnetic interference in microwave electric field sensing. In this work, the concept of electromagnetically induced transparency (EIT) with Rydberg atoms, along with heterodyne mixing techniques, is employed to accurately measure both the DFS and AOA of microwave field within a unified experimental system. The proposed scheme utilizes the dual-coupled beams in the Rydberg atom vapor cell to reduce experimental errors and improve the measurement accuracy. The experimental results indicate that within the frequency measurement range from 11 to 18 GHz, the experimental error in measuring the DFS of different Rydberg states is within ±0.5 Hz, showcasing the wideband tunability of the system. Moreover, the AOA measurement for the echo signal reveal that the measurement error is less than 0.5° within the range from –30° to 35°. This research shows the first instance of simultaneously measuring DFS and AOA within the same Rydberg atom system. Additionally, by introducing the concept of ’relative frequency zero point’ in DFS measurement for the first time, the differentiation of the direction of the DFS can be identified. Furthermore, the accuracy of AOA measurement based on Rydberg atoms has been further improved in this research. Overall, this research provides a novel approach for measuring DFS and AOA using Rydberg atomic system.
Electric field measurement technology with Rydberg atoms has emerged as a forefront technique due to its extra-ordinarily capacity of detecting various electric field parameters, including amplitude, frequency, phase, and polarization. This study presents the development of a Rydberg atomic heterodyne receiver integrated with a linear array of 4-element Rydberg field probes, enabling simultaneous multi-beam forming reception and determination of the angle of arrival at 8.567 GHz. The Rydberg field probe has the advantages of high optical coupling efficiency, strong portability, and low mutual influence.
Atomic sensing and electric field measurements based on the use of the all-optical electromagnetic induction transparency (EIT) spectrum of Rydberg atoms have attracted great interest due to the advantages of self-calibration, Le Système International d'unités traceability, and a broadband spectrum. At the same time, this methodology also promotes the development of atomic sensor technology. We present a novel high-efficiency Rydberg-atom radio-frequency (RF) electric (E) field integrated probe (Rydberg Field Probe or RFP). The high-efficiency RFP consists of a 10 mm cubic 133Cs vapor cell, a dichroic mirror, three collimating lenses, and three fibers. This system can be used to independently control two counterpropagating lasers passing through a vapor cell, easing the design effort. In addition, the overall system efficiency can reach a value of 40.4%, reducing the EIT power broadening doe conventional RFPs. Based on the designed high-efficiency RFP, near-field electric field measurement and imaging of a C-band horn antenna at 4.48 GHz are performed by using the resonant RF field of the 133Cs atomic Rydberg state at room temperature with a spatial resolution of λ/6. These results promote the development of atomic sensing technology and show great application potential for the measurement of measuring high-resolution radio frequency electric fields and arrays of RFPs.
Abstract Recently, the rapid progress of quantum sensing research reveals that Rydberg atoms have great potential in becoming high-precision centimeter-scale antennas for low-frequency fields. In order to facilitate efficient and reliable detection of low-frequency fields via Rydberg atoms, we designed and implemented a heterodyne method based on the linear response to external signals under the condition of Rydberg electromagnetically induced transparency (EIT). Instead of relying on observing changes in the absorption of light by Rydberg atoms, our method focuses on the phase modulation effect on the probe laser induced by low-frequency fields via the Rydberg EIT mechanism and utilizes a special demodulation process to accurately retrieve signals including both amplitude and phase. The general principles of our method apply to both electric and magnetic fields, and it is even possible to realize a combination of both functionalities in the same apparatus. In particular, we experimentally demonstrate the full cycle of operations with respect to both cases. In measuring low-frequency electric fields, we discover that the Rydberg dipole–dipole interaction among atoms induces a linear superposition of Rydberg states with different angular momentum, generating a first-order response corresponding to the signature of the linear Stark effect. As Rydberg atoms have excellent coupling strengths with electric fields, our results indicate that our method can hopefully achieve high-precision performance for practical tasks in the future.
The high polarizability of Rydberg atoms enables the multi-parameters measurement of electromagnetic fields. In this paper, we report on an atomic antenna based on Rydberg atoms in a room temperature vapor cell. The EIT is a destructive interference spectroscopy with a narrow linewidth and can be used to detect small electric fields through Autler-Townes splitting or Stark shifts. In our experiments, we employ cascade-type two-photon excitation electromagnetically induced transparency (EIT) spectroscopy to measure the shift of the Rydberg energy level. We introduce a low-frequency electric field (~kHz frequency) using a built-in electrode technique in the cesium cell. The interaction between the Rydberg atom and electric field induces the Stark shifts, where the amplitude of the electric field is converted into corresponding two-photon detuning by the EIT effect. Furthermore, the amplitude of the low-frequency electric field is converted into an intensity signal of EIT probe beam. Under weak field conditions, it is an approximate linear relationship between EIT transmission signal and input electric field amplitude, enabling measurement of waveform, amplitude, and frequency. We have demonstrated optical measurements of low-frequency electric field using Rydberg atoms. By increasing the power of probe beam and coupling beam, the EIT can increase the response bandwidth from ~MHz to hundreds of MHz. This provides a scalable approach for measuring high-frequency electric fields.
Recently, the rapid progress of quantum sensing research reveals that the Rydberg atoms have great potentials in becoming high-precision centimeter-scale antenna of low-frequency fields. In order to facilitate efficient and reliable detection of low-frequency fields via Rydberg atoms, we design, implement and analyze a special but low-cost and scalable method based on heterodyning processes under the condition of electromagnetically induced transparency (EIT) embedded in typical two-photon ground-Rydberg transition. Instead of relying on observing changes in absorption of light by Rydberg atoms, our method focuses on the phase modulation effect on the probe laser induced by the low-frequency fields via the Rydberg EIT mechanism and utilizes a demodulation process to accurately retrieve the signal. The general principles of our method apply to both electric and magnetic fields and it is even possible to realize the combination of both functionalities in the same apparatus. In particular, we experimentally demonstrate the full cycle of operations with respect to both cases. In the measurement of low-frequency electric fields, we discover that the Rydberg dipole-dipole interaction among atoms induce linear superposition of Rydberg states with different angular momentum that generates a first-order response corresponding to the signature of linear Stark effect. As the Rydberg atoms have excellent coupling strengths with electric fields, our results indicate that our method can hopefully reach high-precision performance for practical tasks in the future.