Article
Physics, Multidisciplinary
Michael Peper, Johannes Deiglmayr
Summary: In this study, homonuclear Cs-2, K-2, and heteronuclear CsK long-range Rydberg molecules were formed in a dual-species magneto-optical trap for K-39 and Cs-133 by one-photon UV photoassociation. The different ground-state-density dependence of homo- and heteronuclear photoassociation rates and the detection of stable molecular ions provided clarification. Bound-bound millimeter-wave spectroscopy of long-range Rydberg molecules was utilized to access molecular states not accessible by one-photon photoassociation, serving as a benchmark for the development of theoretical models.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
J. Andrijauskas, J. Vogel, A. Mokhberi, F. Schmidt-Kaler
Summary: In this study, Rydberg series spectroscopy was performed on a single trapped Ca-40(+) ion to determine the ionization energy and quantum defect values, confirming their scaling properties for Rydberg ions. The precise spectroscopic data obtained can be used for unambiguous addressing of Rydberg levels of Ca+ ions, further facilitating quantum information processing.
PHYSICAL REVIEW LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Motoharu Matsuura
Summary: Power-over-fiber (PWoF) is a promising technology that utilizes optical fibers to transmit power and data signals simultaneously. This study provides an overview of PWoF using different types of optical fibers and presents a practical application for powering remote antenna units in mobile communications. The use of double-clad fibers in PWoF allows for the transmission of high-speed data signals and high-power feed light. Experimental demonstrations and performance comparisons are discussed, with future prospects outlined.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Motoharu Matsuura, Hayato Nomoto, Hikaru Mamiya, Tadanobu Higuchi, Denis Masson, Simon Fafard
Summary: The article demonstrates simultaneous 40-W electric power and optical data transmission through an optical fiber for optically powered remote antenna units in future mobile communication networks. By improving the link design and using a photovoltaic power converter, the electric power delivery is successfully increased to 43.7W with high optical-to-electrical conversion efficiency.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Andrea Giovannini, Jacopo Nanni, Luis Fernandez, Giacomo Paolini, Federico Perini, Enrico Lenzi, Anne-Laure Billabert, Alessandra Costanzo, Jean-Luc Polleux, Diego Masotti, Jean-Marc Laheurte, Giovanni Tartarini
Summary: The study proposes a solution combining Radio over Fiber (RoF) and Time Modulated Arrays (TMA) in In-Building scenarios, where an effective control of the maximum deviation of multiple beams emitted by TMA can be achieved by maintaining a small length difference among the output branches of the optical splitter.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Physics, Applied
Jinlian Hu, Huaqiang Li, Rong Song, Jingxu Bai, Yuechun Jiao, Jianming Zhao, Suotang Jia
Summary: In this study, we demonstrate a continuously tunable electric field measurement based on the far off-resonant AC Stark effect in a Rydberg atomic vapor cell. By mixing an incident weak signal field with a strong far off-resonant field in the Rydberg system, we are able to measure electric fields in the frequency range of 2 to 5 GHz. Our method provides high sensitivity and can be extended to arbitrary frequency measurements.
APPLIED PHYSICS LETTERS
(2022)
Article
Optics
Chanhyun Pak, Matthew J. Schlitters, Scott D. Bergeson
Summary: In this study, frequency-comb-based measurements were used to investigate the Rydberg energy levels of Ca atoms. Counterpropagating laser beams were employed to excite Ca atoms, resulting in symmetric and Gaussian line shapes. By reproducing measurements of known transitions in Cs, the laser metrology and absolute accuracy were verified. The ionization potential of Ca was determined from the measured transition energies.
Article
Physics, Multidisciplinary
Xiao-Jun Zhang, Huan Chang, Jia-Yao Huo, Jin-Hui Wu
Summary: This article investigates the four-wave mixing (FWM) nonlinearity in an ensemble of cold Rydberg atoms. It shows the existence of both local and much larger nonlocal nonlinearity, which can be further enhanced by increasing the atomic density. These findings are of great significance for applications in quantum information processing involving FWM nonlinearity, such as the generation of squeezed or entangled states.
NEW JOURNAL OF PHYSICS
(2022)
Article
Computer Science, Hardware & Architecture
Luiz Augusto Melo Pereira, Luciano Leonel Mendes, Carmelo Jose Albanez Bastos Filho, Arismar Cerqueira Sodre Jr
Summary: Ubiquitous communication, especially in rural areas, is a major challenge for future mobile networks. The use of a centralized radio access network and radio over fiber system can simplify network deployment and reduce costs. However, the nonlinear effects introduced by commonly used components can degrade system performance. Machine learning algorithms offer a promising approach for linearization, as demonstrated by numerical results.
JOURNAL OF OPTICAL COMMUNICATIONS AND NETWORKING
(2023)
Article
Optics
Qinxia Wang, Zhihui Wang, Yanxin Liu, Shijun Guan, Jun He, Chang-Ling Zou, Pengfei Zhang, Gang Li, Tiancai Zhang
Summary: The optical bistability (OB) of Rydberg atoms is explored with cavity-enhanced thermal cesium vapor cell, showing an enhancement of more than one order of magnitude compared with free space. The slope of the phase transition signal at the critical point is enhanced by more than 10 times, indicating a sensitivity enhancement of two orders of magnitude for Rydberg-based sensing and metrology.
Article
Physics, Multidisciplinary
R. Cardman, J. L. MacLennan, S. E. Anderson, Y-J Chen, G. Raithel
Summary: The study introduces a formalism for the photoionization and potential energy curves of Rydberg atoms in ponderomotive optical lattices, demonstrating the impact of lattice-induced photoionization on Rydberg atom lifetimes across different optical lattice depths. The behaviour of photoionization is largely governed by the rapid decrease of photoionization cross sections with increasing angular momentum, lattice-induced angular momentum mixing, and interference between photoionization transition amplitudes in lattice-mixed and free-electron states. In deep optical lattices, angular momentum mixing leads to a complex potential energy curve structure, while in shallower lattices, atoms on low angular momentum curves remain relatively unaffected by mixing and maintain high photoionization rates. Data on photoionization in different lattice depths have potential applications in optical control and high-precision spectroscopy of Rydberg atoms.
NEW JOURNAL OF PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Igor Lima de Paula, Laurens Bogaert, Olivier Caytan, Joris Van Kerrebrouck, Arno Moerman, Muhammad Muneeb, Quinten Van den Brande, Guy Torfs, Johan Bauwelinck, Hendrik Rogier, Piet Demeester, Gunther Roelkens, Sam Lemey
Summary: A low-complexity and efficient mmWave-over-fiber remote antenna unit is proposed for broadband transmission and wide-angle squint-free beam steering. It utilizes an optical beamforming network and an optically enabled 1x4 uniform linear array to achieve high performance and energy efficiency, demonstrating successful optical beamforming.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
David Alexander Anderson, Rachel Elizabeth Sapiro, Georg Raithel
Summary: A portable Rydberg-atom-based radio frequency (RF) electric field measurement instrument is presented, featuring an atomic RF field probe connected to a portable mainframe control unit. The system offers self-calibrated SI-traceable RF measurement and analysis, real-time field and measurement uncertainty readout, and spectral RF waveform visualization. The system is well-suited for SI-traceable RF measurements over multiple bands, providing accurate and reliable results.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Physics, Multidisciplinary
Frederic Hummel, Matthew T. Eiles, Peter Schmelcher
Summary: This study observed a series of conical intersections in the potential energy curves governing both the collision between a Rydberg atom and a ground-state atom and the structure of Rydberg molecules. By using the electronic energy of the Rydberg atom as a synthetic dimension, the von Neumann-Wigner theorem was circumvented. These conical intersections can occur when certain conditions are met, and have a significant impact on the rate of ultracold l-changing collisions.
PHYSICAL REVIEW LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Kota Ito, Mizuki Suga, Yushi Shirato, Naoki Kita, Takeshi Onizawa
Summary: This study introduces a remote beamforming scheme with fixed wavelength allocation for RoF systems using SMF, providing efficient wavelength utilization and complete remote beam control without precise information of optical fiber length. The scheme's beamforming performance is evaluated theoretically and experimentally, showing dependence on optical intensity modulation frequency. Results indicate that narrower wavelength spacing is required for desired beam pattern with higher intensity modulation frequency or more wavelengths. Additionally, experiments confirm the scheme's ability to achieve almost ideal beam patterns and realize beamforming and beamscanning.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Physics, Applied
J. Susanne Otto, Marisol K. Hunter, Niels Kjaergaard, Amita B. Deb
Summary: The data transfer capacity of a communication channel is constrained by the Shannon-Hartley theorem, but can be enhanced by using an array of atom-optical receivers in a single-input-multi-output configuration with spatially distributed probe light beams. The data capacity scales with the number of receivers in the array, and the enhancement is found to be independent of modulation frequency.
JOURNAL OF APPLIED PHYSICS
(2021)
Review
Multidisciplinary Sciences
Niels Kjaergaard
Summary: The article discusses how indistinguishability affects collisions of identical particles and the possible outcomes in different scenarios.
JOURNAL OF THE ROYAL SOCIETY OF NEW ZEALAND
(2021)
Editorial Material
Multidisciplinary Sciences
Niels Kjaergaard, Daniel Schumayer
JOURNAL OF THE ROYAL SOCIETY OF NEW ZEALAND
(2021)
Article
Multidisciplinary Sciences
Amita B. Deb, Niels Kjaergaard
Summary: The Pauli exclusion principle explains many atomic properties such as electronic shell structure. Experimental observations of light scattering showed a significant decrease in scattering from Fermi gas, due to Pauli blocking caused by Fermi-Dirac statistics.
Article
Physics, Applied
R. Thomas, J. S. Otto, M. Chilcott, A. B. Deb, N. Kjaergaard
Summary: This method demonstrates the reduction of number fluctuations in an ultracold atomic sample using real-time feedback, based on a proxy value derived from Faraday rotation measurements. Iteratively removing excess atoms from the sample to converge on a target value is shown to be robust to environmental perturbations and light polarization errors. Number fluctuations were reduced from 3% to 0.45% over several hours, with limitations posed by temperature fluctuations, beam-pointing noise, and photon shot noise.
PHYSICAL REVIEW APPLIED
(2021)
Article
Optics
Matthew Chilcott, James F. E. Croft, Ryan Thomas, Niels Kjaergaard
Summary: We analyze the interplay between a magnetic Feshbach resonance and a shape resonance in cold collisions of ultracold Rb-87 atoms using a quantum defect theory framework. The width of the Feshbach resonance can be tuned over several orders of magnitude by controlling the collision energy and magnetic field. The coincidence of a shape resonance with the Feshbach resonance leads to a significant additional boost, and experimental results show a magnetic width much larger than the predicted Feshbach resonance width by utilizing the shape resonance as a magnifying lens.
Correction
Optics
Bianca J. Sawyer, Milena S. J. Horvath, Eite Tiesinga, Amita B. Deb, Niels Kjaergaard
Article
Computer Science, Information Systems
Matthew Chilcott, Niels Kjaergaard
Summary: The paper presents a flexible wireless monitoring system tailored for dynamic and complex experimental setups encountered in modern research laboratories. Leveraging an Internet-of-Things approach, the platform monitors a wide range of physical parameters via wireless sensor modules that broadcast to a networked computer. The system taps into physical parameters of the ultracold atom machine both via customized sensor modules and by recruiting constituent instruments for diagnostics.
INTERNET OF THINGS
(2021)
Article
Physics, Multidisciplinary
Matthew Chilcott, Ryan Thomas, Niels Kjaergaard
Summary: In quantum mechanics, the interaction between scattering poles in collision experiments has been difficult to observe, but can be revealed by studying ultracold atoms to understand their underlying principles.
PHYSICAL REVIEW RESEARCH
(2021)
