Daniel Kaplan (born 28 April 1941) is a French condensed matter physicist whose main work concerns the electronic properties of semiconductors, magnetic resonance and ultra-short pulse lasers. He is a member of the French Academy of Sciences.
Daniel Kaplan is a physicist working in the fields of condensed matter physics, magnetic resonance and ultra-short pulse laser optics. After graduating from the École Polytechnique (Class of 1960), he joined the Condensed Matter Laboratory headed by Ionel Solomon at the École Polytechnique. He is defending a doctoral thesis on the magnetic resonance of conduction electrons in indium antimonide. [1] In parallel, he is exploring new techniques to detect the magnetic resonance of electrons (spin-dependent recombination) and nuclei (nuclear field effect on magnetoresistance). [2]
From 1970 to 1972 Daniel Kaplan worked in the USA at IBM's T.J. Watson Research Center. He explores, using magnetic resonance, the structure of thin layers of amorphous silicon. It shows that, in pure amorphous silicon, a minimum number of unsatisfied chemical bonds is required to meet the stresses of the structure. [3] These bond breaks produce paramagnetic sites and the reduction in the number of these sites is always due to additional chemical elements such as hydrogen. Hydrogenated amorphous silicon will later become a basic material for the production of large-area electronic devices such as flat screens or photovoltaic panels.
In 1972, he joined the physics laboratory of the Central Research Laboratory of Thomson CSF (now Thales) in Palaiseau. His main research activity is focused on understanding the insulating-metal transition in oxides such as Vanadium Dioxide. [4] The combination of optical, electrical and magnetic resonance measurements clarified the respective roles of the network distortion degeneration lift and the Mott transition in this phase change. At the same time, he is continuing his research on amorphous silicon. It shows that the paramagnetic resonance signals observed on vacuum-cleaved silicon crystal surfaces are due to contamination by small amorphous silicon particles. [5] It also demonstrates the process of hydrogenation of pure amorphous silicon layers with hydrogen plasma. [6] In addition, the mechanism of spin-dependent recombination in silicon is elucidated in a theoretical paper published by Kaplan, Solomon, and Mott. [7]
In 1983, he joined the medical branch of Thomson CSF (Thomson CGR) as Scientific Director. He then supervised research and development in the field of digital radiology, X-ray scanning and magnetic resonance imaging.
In 1988, he became head of Thomson CSF's central research laboratory, which conducts research covering computer science, electronic and optical devices and new techniques for consumer electronics. He was president of the French Physical Society between 1992 and 1994.
In 1993, he left the Thomson CSF group and created the Alloy company to develop an original way of conducting public-private partnership research. The Alloy company hires young researchers to work in public laboratories, in France or abroad, on industrial projects. Daniel Kaplan plays the role of project manager in these actions. He repeatedly presents this mode of operation and its importance in conferences. [8]
In 1999, he founded Fastlite with P Tournois to design and manufacture instruments in the field of ultra-short pulse lasers. The company's flagship product will be an original acousto-optical device (Dazzler™) allowing the electronic programming of the spectral phase of these lasers. [9] This programming is an essential tool for the implementation of the CPA (Chirped Pulse Amplification) method, invented by Mourou and Strickland (Nobel Prize 2018), which has profoundly transformed the performance of ultra-intense lasers. The company will also invent and commercialize a new method for measuring the temporal form of pulses. [10] Daniel Kaplan is currently President of Fastlite, which continues to develop its activity in the field of parametric amplification of ultra-short pulses.
In collaboration with A. Aspect, R. Balian, G. Bastard, J.P. Bouchaud, B. Cabane, F. Combes, T. Encrenaz, S. Fauve, A. Fert, M. Fink, A. Georges, J.F. Joanny, D. Le Bihan, P. Léna, H. Le Treut, J-P Poirier, J. Prost and J.L. Puget, Demain la physique, Odile Jacob editions, 2009 ( ISBN 9782738123053)
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In chemistry, a dangling bond is an unsatisfied valence on an immobilized atom. An atom with a dangling bond is also referred to as an immobilized free radical or an immobilized radical, a reference to its structural and chemical similarity to a free radical.
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Muon spin spectroscopy, also known as μSR, is an experimental technique based on the implantation of spin-polarized muons in matter and on the detection of the influence of the atomic, molecular or crystalline surroundings on their spin motion. The motion of the muon spin is due to the magnetic field experienced by the particle and may provide information on its local environment in a very similar way to other magnetic resonance techniques, such as electron spin resonance and, more closely, nuclear magnetic resonance (NMR).
The history of mass spectrometry has its roots in physical and chemical studies regarding the nature of matter. The study of gas discharges in the mid 19th century led to the discovery of anode and cathode rays, which turned out to be positive ions and electrons. Improved capabilities in the separation of these positive ions enabled the discovery of stable isotopes of the elements. The first such discovery was with the element neon, which was shown by mass spectrometry to have at least two stable isotopes: 20Ne and 22Ne. Mass spectrometers were used in the Manhattan Project for the separation of isotopes of uranium necessary to create the atomic bomb.
In nuclear chemistry and nuclear physics, J-couplings are mediated through chemical bonds connecting two spins. It is an indirect interaction between two nuclear spins that arises from hyperfine interactions between the nuclei and local electrons. In NMR spectroscopy, J-coupling contains information about relative bond distances and angles. Most importantly, J-coupling provides information on the connectivity of chemical bonds. It is responsible for the often complex splitting of resonance lines in the NMR spectra of fairly simple molecules.
The Helically Symmetric Experiment, is an experimental plasma confinement device at the University of Wisconsin–Madison, with design principles that are intended to be incorporated into a fusion reactor. The HSX is a modular coil stellarator which is a toroid-shaped pressure vessel with external electromagnets which generate a magnetic field for the purpose of containing a plasma. It began operation in 1999.
The Staebler–Wronski Effect (SWE) refers to light-induced metastable changes in the properties of hydrogenated amorphous silicon.
A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies to contain them in well-defined beams. Large accelerators are used for fundamental research in particle physics. Accelerators are also used as synchrotron light sources for the study of condensed matter physics. Smaller particle accelerators are used in a wide variety of applications, including particle therapy for oncological purposes, radioisotope production for medical diagnostics, ion implanters for the manufacture of semiconductors, and accelerator mass spectrometers for measurements of rare isotopes such as radiocarbon.
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James S. Hyde was an American biophysicist. He held the James S. Hyde chair in Biophysics at the Medical College of Wisconsin (MCW) where he specialized in magnetic resonance instrumentation and methodology development in two distinct areas: electron paramagnetic resonance (EPR) spectroscopy and magnetic resonance imaging (MRI). He is senior author of the widely cited 1995 paper by B.B. Biswal et al. reporting the discovery of resting state functional connectivity (fcMRI) in the human brain. He also served as Director of the National Biomedical EPR Center, a Research Resource supported by the National Institutes of Health. He was author of more than 400 peer-reviewed papers and review articles and held 35 U.S. Patents. He was recognized by Festschrifts in both EPR and fcMRI.
Gattamraju Ravindra Kumar is an Indian laser physicist and a senior professor of Nuclear and Atomic Physics at Tata Institute of Fundamental Research. Known for his research on Ultrashort pulse and Warm dense matter, Kumar is an elected fellow of the Indian Academy of Sciences and the Indian National Science Academy. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards, for his contributions to physical sciences in 2003. He is also a recipient of the B. M. Birla Science Prize and Infosys Prize.
Erich Spitz is a French engineer and physicist of Moravian German ethnicity.
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