arXiv subjects

Huadong Cheng

Publications and source records attributed to Huadong Cheng.

8 recordsLinked to original sources

arXiv2026

Achieving 100$\,$MHz Instantaneous Bandwidth in a Broadband Rydberg Microwave Sensor

Rydberg atoms have attracted considerable attention in recent years as a novel platform for microwave sensing, owing to their unique physical merits: large transition dipole moments between Rydberg levels and broad frequency coverage. As a critical figure of merit for Rydberg microwave sensors, instantaneous bandwidth serves as a key benchmark for evaluating their viability in practical applications. Previous studies on instantaneous bandwidth remain limited to single-frequency operation, with typical demonstrated values of only tens of megahertz, a constraint that hampers the real-world deployment of this sensing technology. Here, we experimentally achieve an instantaneous bandwidth of over 100$\,$MHz across a broad frequency range of 2.7-20$\,$GHz and realize a sensitivity in the hundreds of nV$\,$cm$^{-1}\,$Hz$^{-1/2}$ range. The physical mechanism lies in the dressed-state coherence and the interference effect between different transition channels. Our work substantially broadens the instantaneous bandwidth of Rydberg microwave sensors and paves the way for their practical deployment in fields such as radar and wireless communications.

physics.atom-ph↗

arXiv2026

Broadband Rydberg Atomic Microwave Sensing with 44.6$\,$MHz Instantaneous Bandwidth

Rydberg atoms have become a promising novel type of microwave sensor due to their excellent physical properties -- broad frequency coverage and large electric dipole moments. High sensitivity and broad instantaneous bandwidth are two indispensable requirements for deployable Rydberg microwave sensors. However, enabling broadband operation while retaining high sensitivity has been a longstanding barrier limiting their applications. We propose and experimentally demonstrate a Rydberg microwave sensor whose instantaneous bandwidth is significantly enhanced via an auxiliary microwave field. By finely modulating the Rydberg energy levels with this field, we broaden the bandwidth substantially while retaining the sensor's inherent high sensitivity. An instantaneous bandwidth of 44.6$\,$MHz ($\pm$22.3$\,$MHz) with a sensitivity of 225.7$\,$nV$\,$cm$^{-1}\,$Hz$^{-1/2}$ is realized in a thermal $^{87}$Rb vapor with the local microwave frequency of 16.03$\,$GHz. Our work delivers concurrent broad instantaneous bandwidth and high sensitivity for Rydberg microwave sensors, paving a technically viable path for their practical deployment in broadband microwave metrology, radar, and wireless communication.

physics.atom-ph↗

arXiv2025

Multi-Dressed-State Engineered Rydberg Electrometry

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 $\mathrm{^{87}Rb}$ vapor-based sensor with a sensitivity of 222.6$\,$nV$\,$cm$^{-1}\,$Hz$^{-1/2}$ and a record instantaneous bandwidth of 76.8$\,$MHz with the local microwave frequency 16.03$\,$GHz. This advancement paves the way for Rydberg-atom technologies in radar, wireless communication, and spectrum monitoring.

physics.atom-ph↗

arXiv2023

High-Sensitive Microwave Electrometry with Enhanced Instantaneous Bandwidth

Rydberg microwave (MW) sensors are superior to conventional antenna-based techniques because of their wide operating frequency range and outstanding potential sensitivity. Here, we demonstrate a Rydberg microwave receiver with a high sensitivity of $62\,\mathrm{nV} \mathrm{cm}^{-1} \mathrm{Hz}^{-1/2}$ and broad instantaneous bandwidth of up to $10.2\,\mathrm{MHz}$. Such excellent performance was achieved by the amplification of one generated sideband wave induced by the strong coupling field in the six-wave mixing process of the Rydberg superheterodyne receiver, which was well predicted by our theory. Our system, which possesses a uniquely enhanced instantaneous bandwidth and high-sensitivity features that can be improved further, will promote the application of Rydberg microwave electrometry in radar and communication.

quant-ph↗

arXiv2016

Improvement in medium-long term frequency stability of integrating sphere cold atom clock

The medium-long term frequency stability of the integrating sphere cold atom clock was improved.During the clock operation, Rb atoms were cooled and manipulated using cooling light diffusely reflected by the inner surface of a microwave cavity in the clock. This light heated the cavity and caused a frequency drift from the resonant frequency of the cavity. Power fluctuations of the cooling light led to atomic density variations in the cavity's central area, which increased the clock frequency instability through a cavity pulling effect. We overcame these limitations with appropriate solutions. A frequency stability of 3.5E-15 was achieved when the integrating time ? increased to 2E4 s.

physics.atom-ph↗

arXiv2016

Observation of magneto-optical rotation effects in cold $^{87}$Rb atoms in an integrating sphere

We present a modified scheme for detection of the magneto-optical rotation (MOR) effect, where a linearly polarized laser field is interacting with cold $^{87}$Rb atoms in an integrating sphere. The rotation angle of the probe beam's polarization plane is detected in the experiment. The results indicate that the biased magnetic field, the probe light intensity and detuning, and the cold atoms' temperature are key parameters for the MOR effect. This scheme may improve the contrast of the rotation signal and provide an useful approach for high contrast cold atom clocks and magnetometers.

physics.atom-ph↗

arXiv2015

A new scheme of compact cold atom clock based on diffuse laser cooling in a cylindrical cavity

We present a new scheme of compact Rubidium cold-atom clock which performs the diffuse light cooling, the microwave interrogation and the detection of the clock signal in a cylindrical microwave cavity. The diffuse light is produced by the reflection of the laser light at the inner surface of the microwave cavity. The pattern of injected laser beams is specially designed to make most of the cold atoms accumulate in the center of the microwave cavity. The microwave interrogation of cold atoms in the cavity leads to Ramsey fringes whose line-width is 24.5 Hz and the contrast of 95.6% when the free evolution time is 20 ms. The frequency stability of $7.3\times10^{-13}τ^{-1/2}$ has been achieved recently. The scheme of this physical package can largely reduce the complexity of the cold atom clock, and increase the performance of the clock.

physics.atom-ph↗

arXiv2010

Measurement of Spatial Distribution of Cold Atoms in An Integrating Sphere

In this paper, we present an experiment to measure the spatial distribution of cold atoms in a ceramic integrating sphere. An quadrupole field is applied after the atoms are cooled by diffuse light produced in the ceramic integrating sphere, thus the shift of atomic magnetic sub-levels are position-dependent. We move the anti-Helmholtz coil horizontally while keeping the probe laser beam resonant with the cold atoms at the zero magnetic field. The absorption of the probe beam gives the number of cold atoms at different position. The results show that at the center of the integrating sphere, less atoms exist due to the leakage of diffuse light into the hole connecting to the vacuum pump. The method we developed in this paper is useful to detect cold atoms in a region where imaging is not possible.

physics.atom-ph↗