Article
Optics
Chuan Bai, Geyang Wang, Wenlong Tian, Li Zheng, Xuan Tian, Yang Yu, Xiaodong Xu, Zhiyi Wei, Jiangfeng Zhu
Summary: This paper demonstrates the direct amplification of femtosecond pulses with the Yb:CaYAlO4 crystal for the first time. A compact and simple two-stage amplifier delivers amplified pulses with high optical-to-optical efficiencies. By using a compressor consisting of prisms and GTI mirrors, a pulse duration of 166-fs is achieved. The beam quality is well maintained thanks to good thermal management.
Article
Chemistry, Analytical
Wen Yi Lv, Li Li Li, Cheng Yi Guan, Chun Mei Li, Cheng Zhi Huang, Shu Jun Zhen
Summary: This study proposes splitting reconstruction and protection-release strategies to address the issue of system leakage in DNA systems. These strategies guide the construction of cascade systems independent of unpurified reactants and allow for the designed order. Additionally, they enhance signal amplification ability for sensitive detection.
ANALYTICAL CHEMISTRY
(2023)
Article
Optics
Julian Schneider, Patrick Forster, Clement Romano, Marc Eichhorn, Christelle Kieleck
Summary: A mid-infrared ZnGeP2 optical parametric oscillator pumped by a Tm3+-doped fiber laser is reported, providing high pulse energies, narrow pulse widths, and high peak powers with excellent efficiency and beam quality. The pump source is an actively Q-switched single oscillator optimized to generate high pulse energies.
Article
Optics
Tiancheng Qi, Dan Li, Guohao Fu, Yousi Yang, Guanzhong Li, Lele Wang, Shanshan Du, Ping Yan, Mali Gong, Qirong Xiao
Summary: In this study, a 10-kW-level high-spectral-purity all-fiber ytterbium-Raman fiber amplifier (Yb-RFA) is successfully demonstrated. By avoiding parasitic oscillation between the cascaded seeds, the Yb-RFA achieves 10.7 kW Raman lasing at 1125 nm using a full-open-cavity Raman seed. This work enables the wavelength extension of high-power fiber lasers with high spectral purity.
Article
Multidisciplinary Sciences
Zhichao Ye, Ping Zhao, Krishna Twayana, Magnus Karlsson, Victor Torres-Company, Peter A. Andrekson
Summary: The study demonstrates the potential of nanophotonics for continuous-wave parametric amplification, enabling applications in various fields such as optical communications, signal processing, and quantum optics.
Article
Optics
Xiaoyi Wang, Ruihuan Wu, Bo Li, Ziyang Wang, Yue Liu, Jia Yuan, Jianping Guo, Hongzhan Liu
Summary: A novel photonic-assisted method for high-gain and narrowband radio frequency signal amplification based on a dual-loop optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. The approach injects the low-power RF signal into a dual-loop OEO below the threshold oscillation state, and achieves maximum gain when the RF signal frequency matches the oscillation mode of the dual-loop OEO. The method provides an average gain greater than 22 dB and a signal-to-noise ratio (SNR) of 40 dB, along with a narrow 3 dB bandwidth of less than 1.2 kHz to effectively remove out-of-band noise and spurious effects.
Article
Computer Science, Information Systems
Kyu-Jin Choi, Jae-Hyun Park, Seong-Kyun Kim, Byung-Sung Kim
Summary: This paper presents the design and performance characteristics of a K-band CMOS differential cascode power amplifier, utilizing thin-oxide and thick-oxide FETs to achieve high supply voltage and output power. The gain degradation caused by the low cut-off frequency of the thick-oxide FET is compensated by its high output resistance when the inter-stage node is neutralized, leading to a high saturated output power and efficiency at 24 GHz frequency in the fabricated chip using 65-nm LP CMOS technology.
Article
Computer Science, Information Systems
Diaaeldin Abdelrahman, Odile Liboiron-Ladouceur, Glenn E. R. Cowan
Summary: This article examines the trade-off between power and sensitivity in optical receivers to improve the energy efficiency of the entire link. The study shows that energy-efficient links require low-power receivers with input capacitance much smaller than that required for optimal noise performance. The analysis suggests that maximizing gain with a value of C-I/C-D = 0.5 is a reasonable choice if the link budget or knowledge of the transmitter side is incomplete.
Article
Chemistry, Analytical
Benish Kanwal, Ammar Armghan, Salman Ghafoor, Ahmad Atieh, Muhammad Sajid, Tasleem Kausar, Jawad Mirza, Yun Lu
Summary: This paper proposes and demonstrates a wideband and flat-gain hybrid optical amplifier (HOA) based on a parallel combination of a praseodymium-doped fiber amplifier (PDFA) and a semiconductor optical amplifier (SOA). The HOA achieves flat gain characteristics in the O+E band and evaluates the transmission performance as a pre-amplifier for different data rates using bit-error rate (BER) analysis.
Editorial Material
Engineering, Electrical & Electronic
Jianguo Ma
Summary: Mobile and wireless communications play crucial roles in our daily lives, and 5G is seen as the convergence of these technologies, leading to extensive research in areas such as millimeter-wave communications. Multiple papers on millimeter-waves, particularly on MIMO technology, have gained significant attention, with specific frequency bands being approved globally for standard 5G communication.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2021)
Article
Optics
Lea Lafargue, Florent Scol, Olivier Vanvincq, Etienne Poeydebat, Geraud Bouwmans, Emmanuel Hugonnot
Summary: We propose an all-fiber integrated system that delivers a single-mode polarized beam. The system utilizes a specially designed solid-core photonic hybrid fiber to maintain the signal polarization and handle high-energy pump pulses for amplifying ultrashort pulses.
Article
Optics
Elodie Boursier, Hadrien Devaine, Alain Braud, Sebastien Montant
Summary: We propose an experimental method for determining the transfer function linewidth of a laser amplifier using a transfer function scan. By using frequency modulation to amplitude modulation (FM-to-AM) temporal modulation measurement as a function of wavelength, we show that the output spectrum of a laser amplifier in Q-switch mode does not accurately represent its transfer function.
Article
Computer Science, Information Systems
Van-Son Trinh, Jeong-Moon Song, Jung-Dong Park
Summary: This paper presents a design strategy for a 280 GHz amplifier in sub-THz range, achieving a robust multistage amplifier with 14 stages in 130 nm SiGe technology. The amplifier offers a compact and improved-noise design by eliminating expensive and lossy baluns, and achieves good matching through the interstage-matching network.
Article
Physics, Applied
Wenlei Shan, Shohei Ezaki
Summary: The numerical model developed can simulate the current-voltage characteristics (IVCs) of reactive magnetron discharges and provide guidance for optimizing plasma processes through analysis of IVCs.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Optics
Xingbin Gu, Jinsheng Liu, Peng Yuan, Xiaoniu Tu, Dongfang Zhang, Jing Wang, Guoqiang Xie, Jingui Ma
Summary: YCOB crystals oriented in both the XZ and XY principal planes possess broadband phase-matching property of intrapulse difference-frequency generation and can generate few-cycle pulses tunable from 2 to 4 μm.
Article
Meteorology & Atmospheric Sciences
Hugues Goosse, Pierre-Yves Barriat, Victor Brovkin, Francois Klein, Katrin J. Meissner, Laurie Menviel, Anne Mouchet
Summary: The fluctuations of atmospheric CO2 concentrations over the preindustrial Common Era are primarily attributed to changes in land carbon storage, influenced by surface air temperature and land use changes. Temperature changes have a potentially large role on the land carbon cycle, but cannot fully explain the magnitude of the CO2 variations. Land use changes and southern hemisphere westerly winds are likely responsible for the observed long term atmospheric CO2 trend.
Correction
Geosciences, Multidisciplinary
Jimin Yu, Delia W. Oppo, Zhangdong Jin, Matthew Lacerra, Xuan Ji, Natalie E. Umling, David C. Lund, Nick McCave, Laurie Menviel, Jun Shao, Chen Xu
Article
Geosciences, Multidisciplinary
Jimin Yu, Delia W. Oppo, Zhangdong Jin, Matthew Lacerra, Xuan Ji, Natalie E. Umling, David C. Lund, Nick McCave, Laurie Menviel, Jun Shao, Chen Xu
Summary: Atmospheric CO2 can critically influence the global climate, but the mechanisms of carbon transfer between the oceanic and atmospheric reservoirs are poorly understood. Recent studies suggest that during the deglaciation, there was a net release of CO2 in the Atlantic sector of the Southern Ocean, contributing to the rise in atmospheric CO2. Additionally, the expansion of Antarctic Intermediate Water was found to be responsible for the rise in atmospheric CO2 during the Bolling warming event.
Article
Multidisciplinary Sciences
V Jomelli, D. Swingedouw, M. Vuille, V Favier, B. Goehring, J. Shakun, R. Braucher, I Schimmelpfennig, L. Menviel, A. Rabatel, L. C. P. Martin, P-H Blard, T. Condom, M. Lupker, M. Christl, Z. He, D. Verfaillie, A. Gorin, G. Aumaitre, D. L. Bourles, K. Keddadouche
Summary: Based on cosmic-ray exposure chronologies, the study reveals that glaciers in the tropical Andes and the north Atlantic regions showed variations on millennial timescales during the Holocene, distinct from other regions. Transient climate simulations and a semi-empirical model also suggest that the Atlantic Meridional Ocean Overturning Circulation (AMOC) plays a significant role in driving glacier changes in these regions. The findings highlight the importance of understanding past AMOC behavior as a potential driver of glacier variations.
NATURE COMMUNICATIONS
(2022)
Article
Geography, Physical
Yun-Chuan Chung, Laurie Menviel, Arianna Marchionne, Horng-Sheng Mii, Veronique Michel, Patricia Valensi, Xiuyang Jiang, Patrick Simon, Elena Rossoni-Notter, Abdelkader Moussous, Heikki Seppa, Yu-Tang Chien, Chung-Che Wu, Hsun-Ming Hu, Chuan-Chou Shen
Summary: In this study, stalagmite records from Observatoire cave in Monaco are used to investigate the climate changes and forcings during the early Weichselian glaciation. The results show a large-scale warming over the Atlantic-Europe territory during the transition from MIS 5b to 5a, accompanied by multi-centennial arid intervals in southern Europe. These changes are attributed to slowdowns of the Atlantic meridional overturning circulation, North Atlantic Oscillation states, and solar activity.
QUATERNARY SCIENCE REVIEWS
(2022)
Article
Geosciences, Multidisciplinary
William R. Gray, Casimir de Lavergne, Robert C. Jnglin Wills, Laurie Menviel, Paul Spence, Mark Holzer, Masa Kageyama, Elisabeth Michel
Summary: The Southern Hemisphere westerly winds have a significant impact on the deep ocean circulation and carbon storage. This study reconstructs the changes in the Southern Hemisphere surface westerlies during the last deglaciation using planktic foraminiferal delta O-18 data and climate models. The results show a 4.8-degree equatorward shift and a 25% weakening of the westerlies during the Last Glacial Maximum compared to the mid-Holocene. Climate models underestimate this shift. According to the reconstruction, the poleward shift in the westerlies closely correlates with the rise in atmospheric CO2.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2023)
Article
Geosciences, Multidisciplinary
J. Yu, R. F. Anderson, Z. D. Jin, X. Ji, D. J. R. Thornalley, L. Wu, N. Thouveny, Y. Cai, L. Tan, F. Zhang, L. Menviel, J. Tian, X. Xie, E. J. Rohling, J. F. McManus
Summary: Ice core measurements show diverse atmospheric CO2 variations during North Atlantic cold periods. This study reveals the impact of multiple ocean ventilation modes on deep-sea carbon storage and atmospheric CO2 changes, providing a comprehensive understanding of carbon cycle adjustments to climate change.
Article
Environmental Sciences
Margit H. Simon, Sunniva Rutledal, Laurie Menviel, Tobias Zolles, Haflidi Haflidason, Andreas Born, Sarah M. P. Berben, Trond M. Dokken
Summary: This study reconstructs the Atlantic water inflow into the Nordic Seas during the Last Glacial Maximum, finding that the Iceland-Faroe Atlantic inflow pathway was important in maintaining seasonal open ocean conditions. Additionally, numerical snow modeling suggests that these ice-free conditions may have contributed to the growth of the Fennoscandian Ice Sheet.
COMMUNICATIONS EARTH & ENVIRONMENT
(2023)
Article
Geosciences, Multidisciplinary
Himadri Saini, Katrin J. Meissner, Laurie Menviel, Karin Kvale
Summary: Through a series of sensitivity experiments, we found an exponential decay relationship between Southern Ocean iron input and the decrease in atmospheric CO2. The study also revealed that the solubility of iron in the ocean has a greater impact on atmospheric CO2 changes, while the regional distribution of iron fluxes has a minor effect. Based on the variability of iron solubility during glacial and interglacial periods, we estimated that iron input caused a CO2 decrease of approximately 9 to 11 ppm at 70 ka, accounting for 12% to 50% of the reconstructed decrease in atmospheric CO2. Additionally, the simulations showed that the decrease in atmospheric CO2 concentration was solely driven by iron fluxes south of the Antarctic polar front, while iron fertilization elsewhere played a negligible role.
CLIMATE OF THE PAST
(2023)
Article
Environmental Sciences
Mengmeng Liu, Iain Colin Prentice, Laurie Menviel, Sandy P. Harrison
Summary: There are uncertainties in estimating the feedback strength of greenhouse gases on climate change. Recent observations do not provide strong constraints, while model-based estimates differ considerably. This study uses rapid climate changes during the last glacial period to estimate the centennial-scale feedback strength of CO2, CH4, and N2O. The feedback estimates obtained indicate that some previously published values for CO2 are unrealistic.
COMMUNICATIONS EARTH & ENVIRONMENT
(2022)
Review
Geosciences, Multidisciplinary
Xavier Crosta, Karen E. Kohfeld, Helen C. Bostock, Matthew Chadwick, Alice Du Vivier, Oliver Esper, Johan Etourneau, Jacob Jones, Amy Leventer, Juliane Mueller, Rachael H. Rhodes, Claire S. Allen, Pooja Ghadi, Nele Lamping, Carina B. Lange, Kelly-Anne Lawler, David Lund, Alice Marzocchi, Katrin J. Meissner, Laurie Menviel, Abhilash Nair, Molly Patterson, Jennifer Pike, Joseph G. Prebble, Christina Riesselman, Henrik Sadatzki, Louise C. Sime, Sunil K. Shukla, Lena Thole, Maria-Elena Vorrath, Wenshen Xiao, Jiao Yang
Summary: Antarctic sea ice plays a critical role in the Earth system, but accurately simulating and projecting future changes in sea ice remains challenging. This paper reviews proxies and reconstructions of sea ice changes throughout the last glacial-interglacial cycle. Diatom fossil assemblages and HBI alkenes in marine sediments, along with chemical proxies in Antarctic ice cores, are commonly used for Antarctic sea ice reconstructions. The reconstructions suggest that sea ice cover during the Last Glacial Maximum was much larger than today, and efforts have also been made to study sea ice during warm periods as an analogue for the future. Limited proxy records covering the complete glacial cycle highlight the need for additional research to better understand the drivers and feedbacks of Antarctic sea ice changes over the past 130,000 years.
CLIMATE OF THE PAST
(2022)
Article
Geosciences, Multidisciplinary
Ryan A. Green, Laurie Menviel, Katrin J. Meissner, Xavier Crosta, Deepak Chandan, Gerrit Lohmann, W. Richard Peltier, Xiaoxu Shi, Jiang Zhu
Summary: Southern hemispheric sea-ice plays a crucial role in the carbon exchange and ocean circulation, making it a key process in past and future climate change. This study analyzes the simulated sea-ice cover during the Last Glacial Maximum (LGM) and compares it with observational data, providing insights into the LGM Southern Ocean state.
CLIMATE OF THE PAST
(2022)
Article
Geosciences, Multidisciplinary
Dipayan Choudhury, Laurie Menviel, Katrin J. Meissner, Nicholas K. H. Yeung, Matthew Chamberlain, Tilo Ziehn
Summary: Recent studies have shown that the ocean carbon sink will weaken in the coming century due to ocean warming and changes in oceanic circulation. This study investigates the carbon cycle response in the Southern Ocean to warmer conditions, finding a significant increase in carbon dioxide outgassing due to higher sea surface temperatures. However, shifts in wind patterns and weaker bottom water formation partially compensate for this increase.
CLIMATE OF THE PAST
(2022)
Article
Environmental Sciences
Laurie Menviel, Aline Govin, Arthur Avenas, Katrin J. Meissner, Katharine M. Grant, Polychronis C. Tzedakis
Summary: The study suggests that the strengthening of the Atlantic Meridional Overturning Circulation plays a dominant role in the abrupt initiation of African Humid Periods, while the presence of residual Northern Hemispheric ice-sheets may delay the peak of the humid periods. Differences in the rate of insolation increase during the penultimate deglaciation compared to the last deglaciation explain the timing differences in the onset of African Humid Periods during these two periods.
COMMUNICATIONS EARTH & ENVIRONMENT
(2021)
Article
Geosciences, Multidisciplinary
Jun Shao, Lowell D. Stott, Laurie Menviel, Andy Ridgwell, Malin Oedalen, Mayhar Mohtadi
Summary: During the early part of the last glacial termination, there was a sharp decline in atmospheric delta(CO2)-C-13, coinciding with a rise in atmospheric CO2. This decline was recorded in marine proxy records from surface and thermocline-dwelling planktic foraminifera, attributing it to the release of respired carbon from the deep ocean. Model results suggest that carbon from the deep ocean first upwelled to the surface in the Southern Ocean before entering the atmosphere, impacting thermocline waters throughout the ocean during the early deglaciation.
CLIMATE OF THE PAST
(2021)
