While Rydberg atoms have shown tremendous potential to serve as accurate and sensitive detectors of microwaves and millimeter waves, their response is generally limited to a single, narrow frequency band around a chosen transition. As a result, their potential to serve as agile and wideband electromagnetic receivers has not been fully realized. Here we demonstrate the use of a mid-infrared, frequency agile optical frequency comb as the coupling laser for three-photon Rydberg atom electrometry. This approach allows for rapid switching between as many as seven individual Rydberg states, allowing for multichannel detection across a frequency range from 1 GHz to 40 GHz. The generality and flexibility of this method for wideband multiplexing is anticipated to have transformative effects in the field of Rydberg electrometry, paving the way for advanced information coding, arbitrary signal detection, and the simultaneous detection of ultra-broadband radiofrequency radiation. Rydberg atoms have the potential to serve as broadband receivers but require lasers with > 100 GHz scan ranges to observe multiple states. We bridge this major gap with an optical frequency comb for rapid preparation of over 7 Rydberg states.
While Rydberg atoms have shown tremendous potential to serve as accurate and sensitive detectors of microwaves and millimeter waves, their response is generally limited to a single, narrow frequency band around a chosen transition. As a result, their potential to serve as agile and wideband electromagnetic receivers has not been fully realized. Here we demonstrate the use of a mid-infrared, frequency agile optical frequency comb as the coupling laser for three-photon Rydberg atom electrometry. This approach allows for rapid switching between as many as seven individual Rydberg states, allowing for multichannel detection across a frequency range from 1 GHz to 40 GHz. The generality and flexibility of this method for wideband multiplexing is anticipated to have transformative effects in the field of Rydberg electrometry, paving the way for advanced information coding, arbitrary signal detection, and the simultaneous detection of ultra-broadband radiofrequency radiation. Rydberg atoms have the potential to serve as broadband receivers but require lasers with > 100 GHz scan ranges to observe multiple states. We bridge this major gap with an optical frequency comb for rapid preparation of over 7 Rydberg states.
Atom-based radio-frequency (rf) electromagnetic field sensing using atomic Rydberg states is a promising technique that has recently attracted significant interest. Its unique advantages, such as extraordinary bandwidth, self-calibration, and all-dielectric sensors, are a tangible improvement over antenna-based methods in applications such as test and measurement and development of broad-bandwidth receivers. Here, we demonstrate how an optical-frequency comb can be used to acquire data in the Autler-Townes regime of Rydberg-atom-based electrometry in a massively parallel fashion, eliminating the need for laser scanning. Two-photon electromagnetically induced transparency readout and preparation of cesium is used for the demonstration. A flat quasicontinuous optical comb is generated with the probe laser at 852 nm using an electro-optic modulator and arbitrary waveform generator. A single-frequency coupling laser at 509 nm is tuned to the Rydberg launch state. An enhanced transmission signal is obtained using self-heterodyne spectroscopy, where the comb signal is beat against a local oscillator derived from the single-frequency probe laser on a fast photodiode. The transmission of each probe-laser comb tooth is observed. We resolve electromagnetically induced transparency peaks with line widths below 5 MHz, with and without laser locking. Radio-frequency electromagnetic fields as low as $66\phantom{\rule{0.2em}{0ex}}\text{\ensuremath{\mu}}{\mathrm{Vcm}}^{\ensuremath{-}1}$ are detected, with sensitivities of $2.3\phantom{\rule{0.2em}{0ex}}\text{\ensuremath{\mu}}{\mathrm{Vcm}}^{\ensuremath{-}1}{\mathrm{Hz}}^{\ensuremath{-}1/2}$. The method offers a significant advantage for reading out electromagnetically induced transparency and Autler-Townes splitting, as neither laser needs to be scanned and slow frequency drifts can be tolerated in some applications. The method enables the detection of the amplitude of a pulsed rf electromagnetic field when the incoming pulse Autler-Townes splits the electromagnetically induced transparency peak.
Rydberg quantum sensors are sensitive to radio-frequency fields across an ultra-wide frequency range spanning megahertz to terahertz electromagnetic waves resonant with Rydberg atom dipole transitions. Here, we demonstrate an atomic millimeter-wave heterodyne receiver employing continuous-wave lasers stabilized to an optical frequency comb. We characterize the atomic receiver in the W-band at a signal frequency of f = 95.992 512 GHz and demonstrate a sensitivity of 7.9 μV/m/Hz with a linear dynamic range in power greater than 70 dB. We develop frequency selectivity metrics for atomic receivers and demonstrate their use in our millimeter-wave receiver, including signal rejection levels at signal frequency offsets Δf/f = 10−4, 10−5, and 10−6; 3, 6, 9, and 12-dB bandwidths; filter roll-off; and shape factor analysis. Our work represents an important advance toward future studies and applications of atomic receiver science and technology in weak millimeter-wave and high-frequency signal detection.
For a Rydberg atom-based sensor to change its sensing frequency, the wavelength of the Rydberg state excitation laser must be altered. The wavelength shifts required can be on the order of 10 nm. A fast-tunable narrow-linewidth laser with broadband tuning capability is required. Here, we present a demonstration of a laser system that can rapidly switch a coupling laser as much as 8 nm in less than 50 μs. The laser system comprises a frequency-stabilized continuous wave laser and an electro-optic frequency comb. A filter enables selection of individual comb lines. A high-speed electro-optic modulator is used to tune the selected comb line to a specific frequency, i.e., an atomic transition. Through Rydberg atom-based sensing experiments, we demonstrate frequency hopping between two Rydberg states and a fast switching time of 400 μs, which we show can be reduced to ∼50 μs with a ping-pong scheme. If updating the RF frequency is not required during frequency hopping, a 200 ns switching time can be achieved. These results showcase the potential of the laser system for advanced Rydberg atom-based radio frequency sensing applications, like communications and radar.
Rydberg atoms, with their giant transition electric dipole moments and abundant energy-level transitions, offer exceptional potential for microwave (MW) electric field sensing, combining high sensitivity and broad frequency coverage. However, simultaneously achieving high sensitivity and broad instantaneous bandwidth in a Rydberg-based MW sensor remains a critical challenge. Here, we propose a multi-dressed-state engineered superheterodyne detection scheme for Rydberg electrometry to overcome this challenge. It is found that the key to simultaneously achieving large instantaneous bandwidth and high sensitivity lies in the coherence of dressed states and the interference between transition channels of dressed states. By strategically engineering the multiple dressed states of Rydberg atoms, we demonstrate a thermal 87Rb vapor-based sensor with a sensitivity of 222.6nVcm−1Hz−1/2 and a record instantaneous bandwidth of 76.8MHz with the local microwave frequency 16.03GHz. This advancement paves the way for Rydberg-atom technologies in radar, wireless communication, and spectrum monitoring.
Communication technologies advance toward secure communication, with frequency hopping communication (FH-C) widely used. However, traditional FH-C is limited by slow hopping speed, narrow bandwidth, and a few hopping points. Rydberg atoms offer a solution but face challenges like poor non-resonant microwave sensitivity and local oscillator synchronization limits. Here, we propose a frequency-hopping receiver based on atomic heterodyne detection that employs high orbital angular momentum (high-OAM) Rydberg states for resonant detection of rapidly hopping radio-frequency signals across multiple, widely separated frequency bands. The high-OAM Rydberg atoms ( l =3,4,5) resonantly detect 315 MHz, 1.7 GHz, and 29.74 GHz RF hopping signals (spanning 6 octaves). With heterodyne detection and a continuous excitation scheme, the system eliminates spectral establishment time, achieving 60 khops/s without transmitter-receiver synchronization, and uses frequency combs to extend hopping points to 5 MHz around resonant frequencies. These advances demonstrate the potential of Rydberg-atom–based receivers for high-speed and wide-band frequency-hopping communication.
Studying Rydberg microwave frequency comb (MFC) spectroscopy helps increase the working bandwidth of the Rydberg receiver.This Letter demonstrates off-resonant Rydberg MFC spectroscopy in a meta-waveguide-coupled Rydberg atomic system.An off-resonant MFC field couples with the Rydberg atoms through a meta-waveguide.The system can receive the microwave field in the working band from 0.5 GHz to 13.5 GHz, and the MFC spectroscopy covers a span of 36 MHz at three different arbitrarily-chosen frequencies of 2 GHz, 3 GHz, and 5.8 GHz.The MFC spectrum that covers a wide range of 125 MHz is also verified.This work is significant for tunable wide-band instant microwave signal detection in the Rydberg atomic system, which is useful in microwave frequency metrology, communication, and radar.