Atom-based receiver for amplitude-modulated baseband signals in high-frequency radio communication

Abstract

An optical probe of cesium Rydberg atoms generated in a thermal vapor cell is used to retrieve a baseband signal modulated onto a 16.98-GHz carrier wave in real-time, demonstrating an atombased quantum receiver suitable for microwave communication. The 60S 1/2 Rydberg level of cesium atoms in the cell is tracked via electromagnetically induced transparency (EIT), an established laser-spectroscopic method. The microwave carrier is resonant with the 60S 1/2 → 60P 1/2 Rydberg transition, resulting in an Autler-Townes (AT) splitting of the EIT signal. Amplitude modulation of the carrier wave results in a corresponding modulation in the optically retrieved AT splitting. Frequency modulation causes a change in relative height of the two AT peaks, which can be optically detected and processed to retrieve the modulation signal. The optical retrieval of the baseband signal does not require electronic demodulation. The method is suitable for carrier frequencies within a range from ∼ 1 GHz to hundreds of GHz. The baseband bandwidth, which is ∼ 20 Hz in the present demonstration, can be increased by faster spectroscopic sampling.1 THz [7], including measurements of microwave (MW) fields [8] and their polarizations [9], and millimeter waves [10]. Small Rydberg-atom field sensors that employ µm-length vapor cells and hollow-core fibers [11] offer significant potential for miniaturization. Recently, Rydberg atoms have also been explored as sensitive, high bandwidth, atomic communications receivers for digital communication [12]. Rydberg atoms have many electronic states with a large number of electric-dipole transitions between them [2], leading to a strong electromagnetic response of these atoms at a dense set of frequencies within the MHz-to THz-range. Rydberg-atom-based field detectors can have a higher sensitivity than detectors with traditional dipole antennas [13], making them suitable for long-distance communication with potential for high-speed parallel operation. In addition, Rydberg atomic receivers can be used for subwavelength imaging of microwave electric-field distributions [14,15].

Rydberg atom based microwave sensing and communication

“…信的可靠性, 信号保真度大于95%, 且信号响应达 到30 dB的动态范围 [74] . 在数字通信方面, 2018年美 国陆军研究实验室将调幅波施加于原子天线, 利用 原子接收端的正交解调实现了移相键控通信方案, 此项工作有望用于配备高带宽超高灵敏度的量子接 收器, 在战场背景噪声干扰下进行高速的频分复用 通信, 从而顺利入选了2018年美国陆军的十大科技 进展 [36] .…”

Continuous-frequency weak electric field measurement with Rydberg atoms

“…An optical Rydberg electromagnetically induced transparency (Rydberg-EIT) spectroscopy and Aulter-Townes(AT) splitting have been employed to measure the RF field over a wide frequency range from 100 MHz 4,5 to over 1 THz 6 , including the measurement of the strength of microwave field and polarizations [7][8][9] , the sub-wavelength microwave imaging 10,11 and the first demonstration of angleof-arrival measurements 12 . The concept of the wireless communication recently based on Rydberg atoms also has been demonstrated, including an amplitude modulation (AM) [13][14][15] , a frequency modulation (FM) 16 , and a phase modulation (PM) 17,18 . Recently, the state-of-the-art Rydberg atomic sensor is achieved using a heterodyne receiver architecture with a sensitivity of 55 nVcm −1 Hz −1/2 19,20 .…”

Deep learning enhanced Rydberg multifrequency microwave recognition

“…using electromagnetically induced absorption [1], electromagnetically induced transparency (EIT) [2,3] and the Autler-Townes effect [3][4][5][6]. The amplitudes [7][8][9][10], phases [10,11] and frequencies [9,10] of MW fields could then be measured with high sensitivity. Based on this measurement sensitivity for MW fields, the Rydberg atom has been used in communications [7,8,12,13] and radar [14] as an atombased radio receiver.…”