Rydberg atoms can serve as an atomic radio frequency receiver for digital and analog information transmission. In this paper, a ladder-type electromagnetically induced transparency system is prepared in a room temperature cesium atomic vapor cell. Microwave electric fields in the Ku band at a frequency of 12.52 GHz and the Ka band at a frequency of 39.80 GHz are used as two-channel communication carriers to demonstrate concurrent information transmission. Analog and digital communications are demonstrated by performing audio and pseudo-random binary sequence signal transmission, respectively. The dynamic range of the proposed system is ∼50 dB, and the communication bandwidth is more than 10 MHz. The obtained results demonstrate the fundamental principles of two- or multi-band communication systems based on different Rydberg final states.
Rydberg atoms can serve as an atomic radio frequency receiver for digital and analog information transmission. In this paper, a ladder-type electromagnetically induced transparency system is prepared in a room temperature cesium atomic vapor cell. Microwave electric fields in the Ku band at a frequency of 12.52 GHz and the Ka band at a frequency of 39.80 GHz are used as two-channel communication carriers to demonstrate concurrent information transmission. Analog and digital communications are demonstrated by performing audio and pseudo-random binary sequence signal transmission, respectively. The dynamic range of the proposed system is ∼50 dB, and the communication bandwidth is more than 10 MHz. The obtained results demonstrate the fundamental principles of two- or multi-band communication systems based on different Rydberg final states.
Up to now, the measurement of radio-frequency (RF) electric field achieved using the electromagnetically-induced transparency (EIT) of Rydberg atoms has proved to be of high-sensitivity and shows a potential to produce a promising atomic RF receiver at resonance between two chosen Rydberg states. In this paper, we study the extension of the feasibility of digital communication via this quantum-based antenna over a continuously tunable RF-carrier at off-resonance. Our experiment shows that the digital communication at a rate of 500 kbps can be performed reliably within a tunable bandwidth of 200 MHz near a 10.22 GHz carrier. Outside of this range, the bit error rate (BER) increases, rising to, for example, 15% at an RF-detuning of ±150 MHz. In the measurement, the time-varying RF field is retrieved by detecting the optical power of the probe laser at the center frequency of RF-induced symmetric or asymmetric Autler-Townes splitting in EIT. Prior to the digital test, we studied the RF-reception quality as a function of various parameters including the RF detuning and found that a choice of linear gain response to the RF-amplitude can suppress the signal distortion. The modulating signal can be decoded at speeds up to 500 kHz in the tunable bandwidth. Our test consolidates the physical basis for reliable communication and spectral sensing over a wider broadband RF-carrier, which paves a way for the concurrent multi-channel communications founded on the same pair of Rydberg states.
Radio reception relies on antennas for the collection of electromagnetic fields carrying information, and receiver elements for demodulation and retrieval of the transmitted information. Here, we demonstrate an atom-based receiver for AM and FM microwave communication with a 3 dB bandwidth in the baseband of ~100 kHz that provides optical circuit-free field pickup, multiband carrier capability, and inherently high field sensitivity. The atom-based receiver exploits field-sensitive cesium Rydberg vapors in a centimeter-sized glass cell, and electromagnetically induced transparency, a quantum-optical effect, as a readout of baseband signals modulated onto carriers with frequencies ranging over four octaves, from C-band to Q-band. Receiver bandwidth, dynamic range and sideband suppression are characterized, and acquisition of audio waveforms of human vocals demonstrated. The atomic receiver is a valuable receiver technology because it does not require antenna structures and is resilient against electromagnetic interference, while affording multiband operation in a single compact receiving element.
Recently, Rydberg atoms have attracted increasing interests for applications as electric field sensors, RF spectrometers, and microwave receivers. In this paper, we present experimental studies of a cesium (Cs) Rydberg atomic microwave receiver and its temporal response characteristics to amplitude modulation (AM), frequency modulation (FM), and binary phase shift keying (BPSK) modulation. The receiver is associated with the Cs Rydberg transitions of n2D5/2 – (n+1)2P3/2 at various frequencies, which is generated by double-resonance laser excitations in a room temperature Cs vapor cell. We use the Electromagnetically Induced Transparency (EIT) and Autler-Townes (AT) effects to directly receive modulated microwave signals and recover the data encoded in the carriers. We demonstrated AM and FM digital data transmissions at data rates up to 1 Mbps and BPSK modulation and demodulation with a clock frequency of 250 kHz. Modulation depths up to 90% are experimentally observed and studied as a function of the modulation clock frequency. We also perform modeling to show that Cs atoms have accessible Rydberg transitions at frequencies covering the range from below GHz to THz for wideband microwave receiver applications across RF systems.
A frequency-hopping communication receiver based on Rydberg atoms, whose carrier frequency changes in accordance with a predetermined sequence, is proposed for what we believe to be the first time and experimentally verified. Based on the coherent population trapping (CPT) effect of atoms, a five-level system is built under the assumption of a constant laser wavelength, where the carrier is the resonance band corresponding to different separated quantum states. Pseudo-random binary sequence (PRBS) and complex image signals undergo keying modulation to achieve frequency-domain hopping reception. In the experiment, a dynamic range of 62 dB is demonstrated. The digital transmission with a data rate of 1 Mbps is performed reliably, within a tunable bandwidth of 50 MHz, an instantaneous bandwidth of 700 kHz and a max hopping rate of 20000 hop/s. The proposed atom-based frequency-hopping receiver is suitable for secure communications, satellite uplinks, quantum cryptography, and high-precision scientific research.
Atomic heterodyne dressed by a local oscillator resonant with Rydberg transitions allows high sensitivity and robust phase measurement of a microwave electric field, but it is typically limited to detection of discrete frequencies within the narrow bandwidth of Rydberg transitions. Here we demonstrate an atomic heterodyne scheme for continuous-frequency electric field measurement based on multilevel Rydberg atoms in a room-temperature vapor cell. Driven by two off-resonant microwaves acting as a tunable local oscillator field, the heterodyne receiver can retrieve the amplitude, phase, and frequency information of signal microwave in a continuous frequency band. In our experiment, the receiver achieves an electric field sensitivity of up to $1.5\phantom{\rule{0.2em}{0ex}}\ensuremath{\mu}\mathrm{V}\phantom{\rule{0.2em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}\phantom{\rule{0.2em}{0ex}}{\mathrm{Hz}}^{\ensuremath{-}1/2}$, 80-dB linear dynamic range, and over 1 GHz of continuous frequency range. We also demonstrate the reliable reception of continuously tunable phase-modulated carriers in the digital communication. This work will facilitate the application of atomic heterodyne in the areas such as radar technique, radio monitoring, and radio astronomy.
To achieve multi-channel parallel transmission of complex signals and enhance spectral efficiency, this study presents a Rydberg atomic antenna system that can demonstrate multiplexed communication schemes. 852-nm and 509-nm lasers are used to excite cesium atoms into Rydberg states in a vapor cell, while employing differential detection techniques to suppress common-mode noise in order to obtain high signal-to-noise ratio electromagnetically induced transparency (EIT) spectra. Under weak electric field conditions, microwave field coupling causes atomic energy level shifts, resulting in two-photon detuning and rendering the EIT transmission intensity almost linearly dependent on the microwave electric field strength. Based on this effect, the integrated electrode configuration in the atomic cell generates a time-varying electric field, which can measure the waveforms, amplitudes, and frequencies of microwave and low-frequency electric fields. According to this principle, we decompose complex chaotic signals into three-dimensional orthogonal electric field components in order to demonstrate time-division multiplexing (TDM) of three-channel signals. Meanwhile, frequency-division multiplexing (FDM) is realized by modulating the x -, y -, z - channels with 3 kHz, 5 kHz, and 4 kHz carriers, respectively. The quantitative analysis of the parameters related to the transmition signal and the reference signal reveals high-fidelity reconstruction, with the fidelity levels reaching 95% for TDM and 90% for FDM. These results validate the feasibility of using optical atomic antennas to reconstruct complex signal waveforms and emphasize the potential of Rydberg-based systems in high-performance electromagnetic field sensing and communication applications.