Richard R. Freeman | |
---|---|
Born | 1944 Corpus, Christi, Texas |
Nationality | American |
Occupation(s) | Physicist, academic and researcher |
Title | Emeritus Edward Teller Professor of Applied Science |
Awards | Fellow, Optical Society of America Fellow, American Physical Society |
Academic background | |
Education | B.S., physics A.M., physics Ph.D., physics |
Alma mater | University of Washington Harvard University |
Doctoral advisor | Norman Ramsey |
Academic work | |
Institutions | University of Washington Ohio State University University of California,Davis |
Richard R. Freeman is an American physicist,academic and researcher. He is an affiliated professor of physics at the University of Washington, [1] a distinguished emeritus professor of mathematical and physical science at Ohio State University,and an emeritus Edward Teller Professor of Applied Science at University of California,Davis. [2]
Freeman’s research specializes in high energy density physics. He has authored over 350 peer-reviewed research papers and holds 6 patents in the fields of lithography and laser processing. His graduate textbook,Electromagnetic Radiation,was published in 2019. [3]
Freeman is a fellow of American Physical Society(APS) [4] and Optical Society of America.
Freeman completed his B.S. degree in physics from University of Washington in 1967. He then studied at Harvard University and earned his A.M. and Ph.D. degrees in physics in 1968 and 1973,respectively. He then completed his postdoctoral studies Massachusetts Institute of Technology in 1976. [2]
Along with his post-doctoral studies,Freeman taught at MIT as a lecturer in physics from 1973 to 1976. From 1976 till 1996,he was then associated with AT&T Bell Laboratories where he served as a member of technical staff,and variously as departmental head of electromagnetic phenomena research,silicon electronics research,advanced lithography research,and strategic planning and business departments. [5]
In 1996,he was appointed by Lawrence Livermore National Laboratory as a deputy associate director of laser programs. In 1998,Freeman left Lawrence Livermore National Laboratory and joined University of California,Davis,where he held positions of chair and Edward Teller Professor at Department of Engineering Applied Science till 2003. He was then recruited by Ohio State University as a distinguished professor of mathematical and physical sciences. During his term at Ohio State University,he served as dean of College of Math and Physical Sciences from 2003 through 2007, [6] as head of the high energy density research group and as the first director of the SCARLET laser facility. [7]
In 2015,Freeman was appointed as an affiliated professor of physics at University of Washington,and as an emeritus professor at Ohio State University and University of California in Davis. [5]
Freeman has conducted research focused on various fields,including atomic physics,high energy density physics,lithography,laser processing,electromagnetics,semiconductors and laser physics.
Freeman focused on the energy level systematics of high-angular-momentum Rydberg states of alkali-metal atoms and described them through a quantum-defect model. His research indicated polarization of core electrons to be the major contribution to the quantum defect. [8]
He studied light absorption in ultra-short scale length plasmas and calculated the absorption of S and P polarized light at a glossy interface. He explained different methods to model the absorption of a short laser pulse as a function of intensity. [9]
Freeman conducted numerical simulations of the energy spectrum of electrons escaping in a cell code large-scale plasma and found a significant difference in the simulated energy spectrum recorded by electron spectrometer and the computations made within the target. He then presented the mechanisms responsible for the resulting difference and also discussed the applications of constraints regarding obtaining electron energy distributions from experimental data. [10]
Freeman worked extensively on lithography during 1990s. He presented Schwarzschild imaging optics for improving alignment stability and demonstrated soft-x-ray projection imaging using radiation from plasma source and ellipsoidal condenser. [11] Using the Schwarzschild camera,magnetically levitated wafer stage and a plasma source,he presented EUV lithography tool and incorporated camera aberrations into physical-optic simulations. Freeman’s research resulted in successful matching of five multilayer reflecting surfaces. [12]
Freeman used the scattering with angular limitation projection electron-beam lithography (SCALPEL) principle to help design the proof-of-concept projection electron-beam lithography system and highlighted the application of the designed technology for the production of sub-0.18 micrometer features. [13]
Freeman extensively studied the changes in atomic structure when an atom is subjected to extremely intense laser light,and published numerous papers explaining the highly modified phoionization yields of atoms irradiated by extremely high intensity laser light compared to that obtained at low intensities. [14]
Freeman developed a method involving detection of ionization products,for measuring peak intensity at the focus of high energy short pulse lasers operating in single shot mode. [15] He conducted a combined study of particle-in-cell and Monte Carlo modeling and investigated the production of Bremsstrahlung radiation during the interaction of ultra-intense laser with a tower-structured target. Freeman found that the targets narrowed the electron angular distribution and generated higher energies. [16]
He published a paper regarding backward-propagating MeV electrons from 1018 W/cm2 laser interactions with water. Freeman’s research indicated that the backward-going,high-energy electrons interacting with the focusing optic resulted in the generation of energetic x-rays in the experiment. He also demonstrated the suppression of high energy radiation by reducing nanosecond-scale pre-pulse. [17] Freeman further presented a diagnostic tool for the alignment of targets in laser-matter interactions in a precise manner. [18]
Atomic, molecular, and optical physics (AMO) is the study of matter–matter and light–matter interactions, at the scale of one or a few atoms and energy scales around several electron volts. The three areas are closely interrelated. AMO theory includes classical, semi-classical and quantum treatments. Typically, the theory and applications of emission, absorption, scattering of electromagnetic radiation (light) from excited atoms and molecules, analysis of spectroscopy, generation of lasers and masers, and the optical properties of matter in general, fall into these categories.
Ionization is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule is called an ion. Ionization can result from the loss of an electron after collisions with subatomic particles, collisions with other atoms, molecules and ions, or through the interaction with electromagnetic radiation. Heterolytic bond cleavage and heterolytic substitution reactions can result in the formation of ion pairs. Ionization can occur through radioactive decay by the internal conversion process, in which an excited nucleus transfers its energy to one of the inner-shell electrons causing it to be ejected.
Plasma diagnostics are a pool of methods, instruments, and experimental techniques used to measure properties of a plasma, such as plasma components' density, distribution function over energy (temperature), their spatial profiles and dynamics, which enable to derive plasma parameters.
A Coulombic explosion is a condensed-matter physics process in which a molecule or crystal lattice is destroyed by the Coulombic repulsion between its constituent atoms. Coulombic explosions are a prominent technique in laser-based machining, and appear naturally in certain high-energy reactions.
A Rydberg atom is an excited atom with one or more electrons that have a very high principal quantum number, n. The higher the value of n, the farther the electron is from the nucleus, on average. Rydberg atoms have a number of peculiar properties including an exaggerated response to electric and magnetic fields, long decay periods and electron wavefunctions that approximate, under some conditions, classical orbits of electrons about the nuclei. The core electrons shield the outer electron from the electric field of the nucleus such that, from a distance, the electric potential looks identical to that experienced by the electron in a hydrogen atom.
The Madison Symmetric Torus (MST) is a reversed field pinch (RFP) physics experiment with applications to both fusion energy research and astrophysical plasmas.
Charles J. Joachain is a Belgian physicist.
Extreme ultraviolet radiation or high-energy ultraviolet radiation is electromagnetic radiation in the part of the electromagnetic spectrum spanning wavelengths shorter that the hydrogen Lyman-alpha line from 121 nm down to the X-ray band of 10 nm. By the Planck–Einstein equation the EUV photons have energies from 10.26 eV up to 124.24 eV where we enter the X-ray energies. EUV is naturally generated by the solar corona and artificially by plasma, high harmonic generation sources and synchrotron light sources. Since UVC extends to 100 nm, there is some overlap in the terms.
Resonance-enhanced multiphoton ionization (REMPI) is a technique applied to the spectroscopy of atoms and small molecules. In practice, a tunable laser can be used to access an excited intermediate state. The selection rules associated with a two-photon or other multiphoton photoabsorption are different from the selection rules for a single photon transition. The REMPI technique typically involves a resonant single or multiple photon absorption to an electronically excited intermediate state followed by another photon which ionizes the atom or molecule. The light intensity to achieve a typical multiphoton transition is generally significantly larger than the light intensity to achieve a single photon photoabsorption. Because of this, subsequent photoabsorption is often very likely. An ion and a free electron will result if the photons have imparted enough energy to exceed the ionization threshold energy of the system. In many cases, REMPI provides spectroscopic information that can be unavailable to single photon spectroscopic methods, for example rotational structure in molecules is easily seen with this technique.
Gurgen Ashotovich Askaryan was a prominent Soviet - Armenian physicist, famous for his discovery of the self-focusing of light, pioneering studies of light-matter interactions, and the discovery and investigation of the interaction of high-energy particles with condensed matter.
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A photoionization mode is a mode of interaction between a laser beam and matter involving photoionization.
Self-focusing is a non-linear optical process induced by the change in refractive index of materials exposed to intense electromagnetic radiation. A medium whose refractive index increases with the electric field intensity acts as a focusing lens for an electromagnetic wave characterized by an initial transverse intensity gradient, as in a laser beam. The peak intensity of the self-focused region keeps increasing as the wave travels through the medium, until defocusing effects or medium damage interrupt this process. Self-focusing of light was discovered by Gurgen Askaryan.
An X-ray laser can be created by several methods either in hot, dense plasmas or as a free-electron laser in an accelerator. This article describes the x-ray lasers in plasmas, only.
A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies, and 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.
Photoelectrochemical processes are processes in photoelectrochemistry; they usually involve transforming light into other forms of energy. These processes apply to photochemistry, optically pumped lasers, sensitized solar cells, luminescence, and photochromism.
Double ionization is a process of formation of doubly charged ions when laser radiation is exerted on neutral atoms or molecules. Double ionization is usually less probable than single-electron ionization. Two types of double ionization are distinguished: sequential and non-sequential.
The index of physics articles is split into multiple pages due to its size.
Philip H. Bucksbaum is an American atomic physicist, the Marguerite Blake Wilbur Professor in Natural Science in the Departments of Physics, Applied Physics, and Photon Science at Stanford University and the SLAC National Accelerator Laboratory. He also directs the Stanford PULSE Institute.
Phillip A. Sprangle is an American physicist who specializes in the applications of plasma physics. He is known for his work involving the propagation of high-intensity laser beams in the atmosphere, the interaction of ultra-short laser pulses from high-power lasers with matter, nonlinear optics and nonlinear plasma physics, free electron lasers, and lasers in particle acceleration.