We demonstrate an atom-based amplitude-modulation (AM) receiver for digital communication with a weak continuous frequency carrier using a Rydberg AC Stark effect in a vapor cell and achieve the operating carrier frequency continuously from 0.1 GHz to 5 GHz at a single Rydberg state. A strong local oscillator (LO) field E LO acts as a gain to shift the Rydberg level to a high sensitivity region, and a weak carrier field E Carr keeps the same frequency with the LO field. The digital baseband signals are encoded onto the E Carr using the amplitude modulation technique with the different modulation frequency. The response of Rydberg atom to the baseband signal is probed via a Rydberg electromagnetically induced transparency (EIT). The measured instantaneous bandwidth of the system is about 230 kHz. To demonstrate the performance of our system for an actual communication, we consider a color image as an example, the received image displays that the bit error rate (BER) is less than 5% when the maximum data transfer rate is about 238 kbps. Meanwhile, our system shows the weak carrier field of E Carr ≥ 13.52 μ V/cm can be used for the practical communication with BER less than 5%. Our works break the limitation that EIT-AT based atomic receivers only operate at the near resonant frequencies of the Rydberg transitions, making this emerging of quantum technology close to the practical application with high sensitivity and broad bandwidth.
We demonstrate an atom-based amplitude-modulation (AM) receiver for digital communication with a weak continuous frequency carrier using a Rydberg AC Stark effect in a vapor cell and achieve the operating carrier frequency continuously from 0.1 GHz to 5 GHz at a single Rydberg state. A strong local oscillator (LO) field E LO acts as a gain to shift the Rydberg level to a high sensitivity region, and a weak carrier field E Carr keeps the same frequency with the LO field. The digital baseband signals are encoded onto the E Carr using the amplitude modulation technique with the different modulation frequency. The response of Rydberg atom to the baseband signal is probed via a Rydberg electromagnetically induced transparency (EIT). The measured instantaneous bandwidth of the system is about 230 kHz. To demonstrate the performance of our system for an actual communication, we consider a color image as an example, the received image displays that the bit error rate (BER) is less than 5% when the maximum data transfer rate is about 238 kbps. Meanwhile, our system shows the weak carrier field of E Carr ≥ 13.52 μ V/cm can be used for the practical communication with BER less than 5%. Our works break the limitation that EIT-AT based atomic receivers only operate at the near resonant frequencies of the Rydberg transitions, making this emerging of quantum technology close to the practical application with high sensitivity and broad bandwidth.
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.
We present a Rydberg atom-based receiver with amplitude modulation (AM) technique for the fifth-generation (5G) millimeter-wave wireless communication in a five-level85Rb atomic coherent system. The carrier microwave (C-MW) field at frequency of 24.12 GHz, corresponding to the 5G millimeter-wave wireless communication band, is encoded by AM technique, and then decoded by Rydberg atom-based receiver with the assistance of an auxiliary microwave (A-MW) field. An atomic response to the C-MW field linking to the signal-to-noise ratio (SNR) of decoded signal, which plays a prerequisite role in 5G millimeter-wave wireless communication with large data transfer capacity, is obtained by investigating the optimal powers of probe laser, coupling laser, and A-MW field. Also, an appropriate AM frequency of 10 kHz, which has an influence on the data transfer capacity, is acquired with 54 dB SNR of decoded signal. Under the abovementioned experimental conditions, the maximum data transfer capacity of 82.5 kbit/s is achieved when the C-MW field power tends to saturate. The bandwidth of Rydberg atom-based receiver is determined as 3.5 GHz, and the instantaneous bandwidth is approximately 106.3 kHz. As a result, 5G signals on three waveforms are transferred with high fidelity, frequency recovery rate, and time synchronization to verify the performance of this receiver for an actual communication. This scheme provides an effective approach for realizing 5G millimeter-wave wireless communication with wide bandwidth, large data transfer capacity, and high fidelity.
Based on Autler-Townes splitting and AC Stark shifts, we present a Rydberg atom-based receiver for determining the amplitude modulation (AM) frequency among a wideband carrier range utilizing a cesium atomic vapor cell.To verify this approach, we measured the signal-to-noise ratio and the data capacity with a 10 kHz AM frequency in the carrier range from 2 GHz to 18 GHz.Without changing the lasers, the working band can be easily extended to a higher range by optimizing the feed antenna and experimental configurations.
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.
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.
Rydberg atoms have been extensively utilized in microwave measurement with high sensitivity, which has great potential in the field of communication. In this study, we discuss the digital communication based on a Rydberg atomic receiver under simultaneously coupling by resonant and near detuning microwaves. In addition, we verify the feasibility of the Rydberg atom-based frequency division multiplexing (FDM) in microwave communication. We demonstrate the principle and performance of the atom-based FDM receiver by applying amplitude modulation (AM) and frequency modulation (FM), respectively. To demonstrate the actual communication performance at different data transfer rates, we consider monochromatic images as an example. The experimental results show that the maximum acceptable data transfer rate of both AM and FM is about 200 kbps, whereas their maximum bit error rates (BER) is less than 5%. When compared with the traditional electronic receiver, this atomic receiver, which is compatible with FDM, has numerous advantages, such as small size, low power consumption, and high sensitivity. Furthermore, this receiver has a strong ability of anti-electromagnetic interference, and the signals transmitted do not interfere with each other in different channels.