Over the past decades, significant progress has been made in the Rydberg-atom-based electrometry. The electric fields measurement with Rydberg atoms features high sensitivity and self-calibration. It has proven to be an excellent quantum receiver for microwave communications. The Rydberg atomic receiver has several advantages: the non-metallic atomic probe does not interfere with the field to be measured, and non-destructive communication can be achieved. The Rydberg atomic sensor converts high-frequency microwaves into spectral detection, thereby the microwave electric field modulation is directly mapped to the atomic spectrum. Therefore, the all-optical detection scheme makes the atomic receiver demodulation circuit free and immune to electromagnetic interference. What’s more, the operational bandwidth of the Rydberg atomic receiver can span from MHz to THz by selecting different Rydberg energy levels. Last but not least, the instantaneous bandwidth of the Rydberg atomic receiver is not limited by the size of the antenna, because the Rydberg atomic receiver breaks a key assumption behind the Chu limit. In recent years, Rydberg atomic communication receivers have attracted much attention from researchers.
Important advances have been achieved in Rydberg atomic receiver. On the one hand, researchers have successfully realized both analog and digital communications by using amplitude modulation, frequency modulation, and phase modulation scheme within Rydberg atomic receiver systems. On the other hand, to enhance the channel capacity, frequency-division multiplexing (FDM) and multiple-input multiple-output (MIMO) communications based on Rydberg atomic receivers have been investigated and demonstrated. The above-mentioned achievements have laid the foundation for the future integration of Rydberg atomic receiver technology into existing 5G wireless communication systems. The shortcoming of Rydberg atomic receivers is mainly reflected in insufficient instantaneous bandwidth (~10 MHz), which limits the channel capacity of the receiver system.
Rydberg atomic communication receivers are expected to be integrated and merged into existing wireless communication systems, improving the communication range of wireless communications. This paper reviews the progress of communication receivers based on Rydberg atoms and introduces the schemes and experimental setups of Rydberg atomic communication receivers in detail, and discusses its future development direction and trends.