Enhancing High-Order-Harmonic Generation By Time Delays Between Two-Color, Few-Cycle Pulses, 2017 University of Nebraska - Lincoln
Enhancing High-Order-Harmonic Generation By Time Delays Between Two-Color, Few-Cycle Pulses, Dian Peng, Liang-Wen Pi, M. V. Frolov, Anthony F. Starace
Anthony F. Starace Publications
Use of time delays in high-order-harmonic generation (HHG) driven by intense two-color, few-cycle pulses is investigated in order to determine means of optimizing HHG intensities and plateau cutoff energies. Based upon numerical solutions of the time-dependent Schrõdinger equation for the H atom as well as analytical analyses, we show that introducing a time delay between the two-color, few-cycle pulses can result in an enhancement of the intensity of the HHG spectrum by an order of magnitude (or more) at the cost of a reduction in the HHG plateau cutoff energy. Results for both positive and negative time delays as well ...
Designing Novel Nanostructured Permanent Magnets, 2017 University of Nebraska at Omaha
Designing Novel Nanostructured Permanent Magnets, Ali Al Kadhim
Student Research and Creative Activity Fair
Rare earth element based alloys have been the source of high performance magnetic alloys, and have played a paramount role in the development of various technologies, including: memory devices (such as credit cards, random-access memory), sensors, and various biomedical applications. However, there is a tremendous need to replace rare earth metals with material with powerful magnetic properties. Our group recently found CrTe-based materials that show very promising magnetic properties in nanostructured form. The magnetic modeling of such material in nanostructured form prior to their fabrication demonstrates their magnetic properties in bulk form. In this project, we investigate the behavior of ...
Improving Sers-Based Readout Strategy For Biomarker Detecting Immunoassays, 2017 U.N.O. Physics Department
Improving Sers-Based Readout Strategy For Biomarker Detecting Immunoassays, Joseph Smolsky
Student Research and Creative Activity Fair
Detection and monitoring of disease biomarkers increases probability of successful disease treatment. Surface enhanced Raman scattering (SERS) has several advantages over conventional readout strategies utilized in detecting immunoassays. SERS provides a method for chemical characterization based on molecular vibrational spectra. Raman signals are typically weak and need to be enhanced. This can be done using plasmons in nanoparticles of noble metals, we use gold (Au). Molecules with known spectra, Raman reporter molecules (RRM), can be adsorbed to Au nanoparticles. This enhances the Raman signal of the RRM when illuminated by a laser of optimal wavelength. Adding antibodies to nanoparticles modified ...
Progress Towards Terahertz Acoustic Phonon Generation In Doping Superlattices, 2017 Marshall University
Progress Towards Terahertz Acoustic Phonon Generation In Doping Superlattices, Thomas E. Wilson
Thomas E. Wilson
Progress is described in experiments to generate coherent terahertz acoustic phonons in silicon doping superlattices by the resonant absorption of nanosecond-pulsed far-infrared laser radiation. Future experiments are proposed that would use the superlattice as a transducer in a terahertz cryogenic acoustic reflection microscope with sub-nanometer resolution.
Phonon Interference In Crystalline And Amorphous Confined Nanoscopic Films, 2017 Marshall University
Phonon Interference In Crystalline And Amorphous Confined Nanoscopic Films, Zhi Liang, Thomas E. Wilson, Pawel Keblinski
Physics Faculty Research
Using molecular dynamics phonon wave packet simulations, we study phonon transmission across hexagonal (h)-BN and amorphous silica (a-SiO2) nanoscopic thin films sandwiched by two crystalline leads. Due to the phonon interference effect, the frequency-dependent phonon transmission coefficient in the case of the crystalline film (Si|h-BN|Al heterostructure) exhibits a strongly oscillatory behavior. In the case of the amorphous film (Si|a-SiO2|Al and Si|a-SiO2|Si heterostructures), in spite of structural disorder, the phonon transmission coefficient also exhibits oscillatory behavior at low frequencies (up to ∼1.2 THz), with a period of oscillation consistent ...
Tunneling Assisted Forbidden Transitions In The Single Molecule Magnet Ni4, 2017 University of Massachusetts - Amherst
Tunneling Assisted Forbidden Transitions In The Single Molecule Magnet Ni4, Yiming Chen
Doctoral Dissertations May 2014 - current
This dissertation presents work in exploring novel quantum phenomena in singlemolecule magnets (SMMs) and superconducting circuits. The degree of the freedom studied is the magnetic moment of a single molecule and the flux quantum trapped in a superconducting ring. These phenomena provide us with new insights into some basic questions of physics and may also find their application in quantum computing.
The molecule we studied is Ni4 ([Ni4(hmp)(dmp)Cl]4) which can be treated as a spin-4 magnet. The large magnetic anisotropy of the molecule leads to bistability of the magnetic moment at low temperatures, with spin-up and ...
Breit-Pauli Atomic Structure Calculations For Si Iii, 2016 Clark Atlanta University
Breit-Pauli Atomic Structure Calculations For Si Iii, Christine D. Griffin
Electronic Theses & Dissertations Collection for Atlanta University & Clark Atlanta University
Theoretical study of energy levels, oscillator strengths, transition probabilities, and lifetimes of Si III lines has been reported in this thesis. These atomic parameters are required for the interpretation of emission and absorption lines of Si III and for the modeling of astrophysical plasmas including Galactic High Velocity Clouds (HVCs), the Sun, and white dwarf stars. We used Hartree-Fock (HF) and Multiconfiguration Hartree-Fock (MCHF) methods in our calculations. We have considered 58 levels of the 3s2, 3s3p, 3p2, 3s3d, 3s4s, 3s4p, 3s4d, 3s4f, 3s5s, 3s5p, 3s5d, 3s6s, and 3s5f configurations. The relativistic corrections are included in Breit-Pauli approximation ...
Linear Feedback Stabilization For A Continuously Monitored Qubit, 2016 Chapman University
Linear Feedback Stabilization For A Continuously Monitored Qubit, Taylor Lee Patti, A. Chantasri, Justin Dressel, A. N. Jordan
Student Research Day Abstracts and Posters
In quantum mechanics, standard or strong measurement approaches generally result in the collapse of an ensemble of wavefunctions into a stochastic mixture of eigenstates. On the other hand, continuous or weak measurements have the propensity to dynamically control the evolution of quantum states over time, guiding the trajectory of the state into non-trivial superpositions and maintaining state purity. This kind of measurement-induced state steering is of great theoretical and experimental interest for the harnessing of quantum bits or "qubits", which are the fundamental unit of the emerging quantum computer. We explore continuous measurement-based quantum state stabilization through linear feedback control ...
Cavity Ringdown Spectroscopy In Nitrogen/Oxygen Mixtures In The Presence Of Alpha Radiation, 2016 University of Southern Mississippi
Cavity Ringdown Spectroscopy In Nitrogen/Oxygen Mixtures In The Presence Of Alpha Radiation, Sidney John Gautrau
This research was part of an effort to experimentally validate computational models under development for radiation-induced atmospheric effects. Cavity Ringdown Spectroscopy (CRDS) was used to measure the concentration of chemical products generated as a result of radiation interactions in a controlled atmosphere. Experiments were conducted in a vacuum chamber interfaced with a gas introduction system that controlled the initial atmospheric composition. A quadrupole mass spectrometer and tunable dye laser were integrated to confirm initial atmospheric composition, and provide wavelength flexibility for detecting a variety of chemical products generated by radiation interactions. CRDS measurements were made for ozone production resulting from ...
Experimental Study On The Production Of Negative Ion Copper Clusters And Applications, 2016 University of Tennessee, Knoxville
Experimental Study On The Production Of Negative Ion Copper Clusters And Applications, Ran Chu
At the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratories (ORNL), we investigated the formation, production and potential application of negative-ion copper clusters using mass distributions of negative-ion copper clusters obtained by bombarding various copper samples with Cs ions. The Cu samples – in very large mass-selected clusters Cu (e.g. n=54) – included natural Cu, isotopically enriched copper-63 and copper-65, and electroformed ultra-clean Cu. Mass spectra of negative copper cluster produced by Cs sputter source size up to 50 are shown for the first time.
Three main features were observed for all four copper samples: the intensity ...
Properties Of The Schrödinger Theory Of Electrons In Electromagnetic Fields, 2016 CUNY Graduate Center and CUNY Brooklyn College
Properties Of The Schrödinger Theory Of Electrons In Electromagnetic Fields, Viraht Sahni, Xiao-Yin Pan
Publications and Research
The Schrödinger theory of electrons in an external electromagnetic field can be described from the perspective of the individual electron via the ‘Quantal Newtonian’ laws (or differential virial theorems). These laws are in terms of ‘classical’ fields whose sources are quantal expectations of Hermitian operators taken with respect to the wave function. The laws reveal the following physics: (a) In addition to the external field, each electron experiences an internal field whose components are representative of a specific property of the system such as the correlations due to the Pauli exclusion principle and Coulomb repulsion, the electron density, kinetic effects ...
A Measuring Method For Abundance Of Uranium Components Based On Active Source Of Neutron, 2016 South West University of Science and Technology
A Measuring Method For Abundance Of Uranium Components Based On Active Source Of Neutron, Li Li, Gen Hu, Keqi Liu
The 8th International Conference on Physical and Numerical Simulation of Materials Processing
No abstract provided.
Diffractive Imaging Of Coherent Nuclear Motion In Isolated Molecules, 2016 University of Nebraska-Lincoln
Diffractive Imaging Of Coherent Nuclear Motion In Isolated Molecules, Jie Yang, Markus Guehr, Xiaozhe Shen, Renkai Li, Theodore Vecchione, R. N. Coffee, Jeff Corbett, Alan Fry, Nick Hartmann, Carsten Hast, Kareem Hegazy, Keith Jobe, Igor Makasyuk, Joseph Robinson, Matthew S. Robinson, Sharon Vetter, Stephen Weathersby, Charles Yoneda, Xijie Wang, Martin Centurion
Martin Centurion Publications
Observing the motion of the nuclear wave packets during a molecular reaction, in both space and time, is crucial for understanding and controlling the outcome of photoinduced chemical reactions. We have imaged the motion of a vibrational wave packet in isolated iodine molecules using ultrafast electron diffraction with relativistic electrons. The time-varying interatomic distance was measured with a precision 0.07 Å and temporal resolution of 230 fs full width at half maximum. The method is not only sensitive to the position but also the shape of the nuclear wave packet.
Investigation Of Multi-Photon Excitation In Argon With Applications In Hypersonic Flow Diagnostics, 2016 Old Dominion University
Investigation Of Multi-Photon Excitation In Argon With Applications In Hypersonic Flow Diagnostics, Jack L. Mills
Physics Theses & Dissertations
Non-intrusive ﬂow diagnostics are essential for studying the physics of hypersonic ﬂow wake regions. To advance the development of next generation hypersonic vehicles and to improve computational ﬂuid dynamics techniques in the hypersonic regime, NASA needs a suitable non-intrusive diagnostic technique to measure velocity, density, and temperature. We will present our work on developing a seedless, non-intrusive diagnostic technique using excited state argon atoms, prepared via multi-photon excitation. In this dissertation, we report results on the ﬁrst phase of this hypersonic wake measurement project. In particular, we have redesigned and characterized the performance of a high energy, nanosecond pulsed Ti ...
Feasibility Of The Use Of Neutron Activation Analysis Techniques In An Underwater Environment, 2016 Western Kentucky University
Feasibility Of The Use Of Neutron Activation Analysis Techniques In An Underwater Environment, Michael D. Chick
Masters Theses & Specialist Projects
Elements when bombarded with neutrons emit a gamma ray that is characteristic of the isotope that underwent a neutron induced nuclear reaction; this is known as neutron activation. The characteristic gamma energy of an isotope can then be detected and recorded. One can then analyze the gamma energies captured and determine the elemental makeup of the sample. This form of analysis can be used in an underwater environment making it potentially a valuable tool for agencies tasked with maritime security of ports and waterways, or clean-up operations. This thesis will focus on the feasibility of neutron interrogation using pulsed fast ...
Control Of Spontanous Emission From Quantum Emitters Using Hyperbolic Metamaterial Substrates, 2016 The Graduate Center, City University of New York
Control Of Spontanous Emission From Quantum Emitters Using Hyperbolic Metamaterial Substrates, Tal Galfsky
All Graduate Works by Year: Dissertations, Theses, and Capstone Projects
Hyperbolic metamaterials (HMMs) are so named for possessing a hyperboloid-shaped dispersion which gives rise to a large photonic density of states. Quantum emitters placed inside or in the near-field of a HMM have been shown to exhibit strong enhancement of spontaneous emission due to the increase in available states. This thesis focuses on enhancing spontaneous emission of quantum emitters in optical frequencies by utilizing multilayered metal/dielectric composites that form these highly anisotropic metamaterials. In conjunction with the enhanced decay rate we experimentally demonstrate two methods for shaping and directing radiation trapped in the HMM into free space by employing ...
Imaging Population Transfer In Atoms With Ultrafast Electron Pulses, 2016 Purdue University
Imaging Population Transfer In Atoms With Ultrafast Electron Pulses, Hua-Chieh Shao, Anthony F. Starace
Anthony F. Starace Publications
We propose the use of ultrafast electron diffraction (UED) to image a controllable, laser-driven coherent electron population transfer in lithium atoms with currently available femtosecond electron pulses. Our simulations demonstrate the ability of ultrafast electrons to image such an electronic population transfer, thus validating UED as a direct means of investigating electron dynamics. Provided the incident electron pulses have sufficient temporal resolution, the diffraction images are shown to resolve also the relative phases of the target electronic wave functions.
Quantum Cascade Laser Measurements Of Line Intensities, N2-, O2- And Ar- Collisional Broadening Coefficients Of N2o In The L3 Band Near 4.5 Μm, 2016 Paul Scherrer Institute (PSI)
Quantum Cascade Laser Measurements Of Line Intensities, N2-, O2- And Ar- Collisional Broadening Coefficients Of N2o In The L3 Band Near 4.5 Μm, Et-Touhami Es-Sebbar, Meriem Meriem Deli, Aamir Farooq
Dr. Et-touhami Es-sebbar
Enhancement Of Hopping Conductivity By Spontaneous Fractal Ordering Of Low-Energy Sites, 2016 West Chester University of Pennsylvania
Enhancement Of Hopping Conductivity By Spontaneous Fractal Ordering Of Low-Energy Sites, Tianran Chen, Brian Skinner
Variable-range hopping conductivity has long been understood in terms of a canonical prescription for relating the single-particle density of states to the temperature-dependent conductivity. Here we demonstrate that this prescription breaks down in situations where a large and long-ranged random potential develops. In particular, we examine a canonical model of a completely compensated semiconductor, and we show that at low temperatures hopping proceeds along self-organized, low-dimensional subspaces having fractal dimension d = 2. We derive and study numerically the spatial structure of these subspaces, as well as the conductivity and density of states that result from them. One of our prominent ...
Infrared Skin Damage Thresholds From 1319-Nm Continous-Wave Laser Exposures, 2016 Fort Hays State University
Infrared Skin Damage Thresholds From 1319-Nm Continous-Wave Laser Exposures, Gavin D. Buffington, Clifton D. Clark
A series of experiments were conducted in vivo using Yucatan miniature pigs (Sus scrofa domestica) to determine thermal damage thresholds to the skin from 1319-nm continuous-wave Nd:YAG laser irradiation. Experiments employed exposure durations of 0.25, 1.0, 2.5, and 10 s and beam diameters of ∼0.6 and 1 cm. Thermal imagery data provided a time-dependent surface temperature response from the laser. A damage endpoint of fifty percent probability of a minimally visible effect was used to determine threshold for damage at 1 and 24 h postexposure. Predicted thermal response and damage thresholds are compared with a ...