Physics Commons^™

Sub-Micron Parallel Laser Direct-Write, Christina Othon, Arnoldo Laracuente, H Ladoucuer, Bradley Ringeisen

Christina M Othon

We have developed a modified laser induced forward transfer (LIFT) technique which allows for the parallel deposition of hundreds of sub-micron features. The approach utilizes a self-assembled monolayer of monodisperse polystyrene microspheres as the focusing element. A monolayer of close-packed microspheres is formed on top of an ultra-thin quartz support (25 m thick), and a metallic thin film is then deposited on the underside of the quartz. This approach is different from previous parallel microsphere-assisted LIFT experiments that required the deposition of metal directly onto the surface of the periodic microsphere structure. For this study, an 800 nm, 130 fs …

Gravitational Wave Burst Source Direction Estimation Using Time And Amplitude Information, J. Markowitz, M. Zanolin, L. Cadonati, E. Katsavounidis

Michele Zanolin

Switchable Polarization-Independent Liquid-Crystal Fabry-Perot Filter, Enkh-Amgalan Dorjgotov, Achintya K. Bhowmik, Philip J. Bos

Philip J. Bos

A new approach to a polarization-independent twisted liquid-crystal (LC) structure, where phase difference between orthogonal eigenmodes is tuned to be an integer multiple of 2 pi, is demonstrated with a numerical model. For select wavelengths, polarization-independent operation can be achieved by tuning the twist rate and thickness of the LC cavity Applications can be found in polarization-independent switches and field sequential wavelength selection devices.

International Terrorism:Role ,Responsibility And Operation Of Media Channles, Ratnesh Dwivedi Mr

Ratnesh Dwivedi

"Terrorism" is a term that cannot be given a stable defintion. Or rather, it can, but to do so forstalls any attempt to examine the major feature of its relation to television in the contemporary world. As the central public arena for organising ways of picturing and talking about social and political life, TV plays a pivotal role in the contest between competing defintions, accounts and explanations of terrorism. Which term is used in any particular context is inextricably tied to judgemements about the legitimacy of the action in question and of the political system against which it is directed. …

Material Damage From Ultrashort Bursts Of Light, Jeremy Gulley

Jeremy R. Gulley

No abstract is currently available.

All-Optical Suppression Of Relativistic Self-Focusing Of Laser Beams In Plasmas, Serguei Y. Kalmykov, Sunghwan A. Yi, Gennady Shvets

Serge Youri Kalmykov

It is demonstrated that a catastrophic relativistic self-focusing (RSF) of a high-power laser pulse can be prevented all-optically by a second, much weaker, copropagating pulse. RSF suppression occurs when the difference frequency of the pulses slightly exceeds the electron plasma frequency. The mutual defocusing is caused by the three-dimensional electron density perturbation driven by the laser beat wave slightly above the plasma resonance. A bi-envelope model describing the early stage of the mutual defocusing is derived and analyzed. Later stages, characterized by the presence of a strong electromagnetic cascade, are investigated numerically. Stable propagation of the laser pulse with weakly …

Homogeneous Dbd In N2: 1) Lif, Talif And Electrical Measurements, N. Gherardi, Et. Es-Sebbar, C. Sarra-Bourret, N. Naudé, F. Massines

Dr. Et-touhami Es-sebbar

In this paper we compare two different discharges that can be obtained in a DBD configuration, that is to say the filamentary discharge (usual regime in atmospheric DBD) with the Atmospheric Pressure Townsend Discharge (APTD), which is a homogeneous regime obtained in nitrogen atmosphere. The aim is to help in the understanding of the processes which control the transition from one regime to the other. To do so, the discharge is characterized through electrical measurements, coupled with optical diagnostics among which Laser Induced Fluorescence (LIF) for radical density measurements. The influence of the addition of small quantities of additives on …

Colloidal Micromotor In Smectic A Liquid Crystal Driven By Dc Electric Field, Antal Jakli, Bohdan Senyuk, Guangxun Liao, Oleg Lavrentovich

Antal Jakli

Converting linear stimulus to rotation has endless examples in virtually all scales of the universe. One of the interesting examples is Quincke rotation, a spinning rotation of a dielectric sphere neutrally buoyant in an isotropic fluid caused by a unidirectional DC electric field. Recently Quincke rotation has been reported in liquid crystalline (LC) phases, and it was noted that spinning triggers a translational motion normal to the electric field and the rotation axis. In this work, we explain the translation of spinning spheres as a result of hydrodynamic interaction with the bounding walls. We also describe a unique orbiting motion: …

Active Species Generation Of Homogeneous Dbd In N2: Experiment And Modelling, N. Gherardi, Et. Es-Sebbar, C. Sarra-Bourret, N. Naudé, F. Massines, D. Tzyganov, P. Ségur, S. Pancheshnyi

Dr. Et-touhami Es-sebbar

No abstract provided.

Carbon Nanotube Doped Liquid Crystal Ocb Cells: Physical And Electro-Optical Properties, Shin-Ying Lu, Liang-Chy Chien

Liang-Chy Chien

We report single-wall carbon nanotube (CNT) doped liquid crystal materials which show significant improvement in the response time for optical controlled birefringence (OCB) cells. Four different types of liquid crystals (LCs) were chosen to mix with CNTs and they demonstrated similar results in improving the response time. Experimental results show that the anchoring energy at alignment layers has been changed by CNT doping. CNTs were attracted to the alignment layer and modified the property of the surface. The anchoring enhancement is due to the pi-pi electron stacking between the CNTs, LC molecules and alignment layers.

Investigation Of Stun Guns As Intentional Electromagnetic Interference (Emi) Sources, George H. Baker, Ryan C. Tuttle

George H Baker

Because the operation and control of most critical infrastructures are highly dependent on electronics, it is important to understand the vulnerability of those electronics to intentional electromagnetic interference (EMI). The possibility of interference using readily available consumer devices is a particular concern. We investigated the feasibility and effectiveness of using compact stun guns to intentionally interfere with electronic systems. Test articles included individual computers and computers networked through a central hub. 60KV and 600KV devices were used in the experiments. Results indicate that stun guns are effective in disabling digital electronic systems.

Surface Ion-Electron Recombination As The Main Source Of Atoms In Flowing N2 Dbd, D. Tsyganov, Et. Es-Sebbar, S. Pancheshnyi, N. Gherardi, P. Ségur, F. Massines

Dr. Et-touhami Es-sebbar

No abstract provided.

Talif Quantification Of Nitrogen Atoms Applied To Experimental Simulation Of Titan’S Atmosphere, Et. Es-Sebbar, Y. Benilan, E. Arzoumanian, M.-C. Gazeau

Dr. Et-touhami Es-sebbar

No abstract provided.

S.E.T.U.P., A New Program Of Representative Simulations Of Titan’S Atmosphere: Current Status, M-C. Gazeau, E. Arzoumanian, Y. Benilan, Et. Es-Sebbar, A. Jolly, S. Perrier, C. Romanzin

Dr. Et-touhami Es-sebbar

No abstract provided.

Report Of The Commission To Assess The Threat To The United States From Emp Attack: Critical National Infrastructures, William R. Graham

George H Baker

The physical and social fabric of the United States is sustained by a system of systems; a complex and dynamic network of interlocking and interdependent infrastructures (“critical national infrastructures”) whose harmonious functioning enables the myriad actions, transactions, and information flow that undergird the orderly conduct of civil society in this country. The vulnerability of these frastructures to threats — deliberate, accidental, and acts of nature — is the focus of greatly heightened concern in the current era, a process accelerated by the events of 9/11 and recent hurricanes, including Katrina and Rita. This report presents the results of the Commission’s …

Long Range Electromagnetic Effects Involving Neutral Systems And Effective Field Theory, Br Holstein

Barry R Holstein

We analyze the electromagnetic scattering of massive particles with and without spin wherein one particle (or both) is electrically neutral. Using the techniques of effective field theory, we isolate the leading long distance effects, both classical and quantum mechanical. For spinless systems results are identical to those obtained earlier via more elaborate dispersive methods. However, we also find new results if either or both particles carry spin.

Chiral Perturbation Theory: An Effective Field Theory, Br Holstein

Barry R Holstein

The concept of an effective field theory (EFT), i.e. a theory which is valid only in a limited range of parameter space, is one which has become highly developed recently. After presenting familiar examples from the realms of classical and quantum mechanics together with condensed matter physics, we show that QCD has an intriguing parallel with superconductivity in that, by using quark–antiquark (mesonic) degrees of freedom and exploiting the symmetries of the theory, a useful and powerful theory–chiral perturbation theory–results, which offers a complete and rigorous description of low energy particle and nuclear physics.

The Study Of Optogalvanic Effect Associated With The 1s States Of Neon, Naveed Piracha, K. Nesbett, S. Marotta

Naveed K. Piracha

We report on the temporal evolution of the optogalvanic signals in neon using a commercial hollow cathode lamp in conjunction with a Nd:YAG pumped dye laser system. We have recorded transitions excited from each of the neon 1s states over a range of discharge current to investigate the dominant physical processes responsible for the optogalvanic effect in neon discharges. The decay rates associated with the four 1s levels have been obtained using a mathematical rate equation model. A linear relationship between the decay rates and the discharge current has been found and the effective lifetimes and the electron collisional rate …

The Peculiar Volatile Composition Of Comet 8p/Tuttle: A Contact Binary Of Chemically Distinct Cometesimals?, Boncho P. Bonev, Michael J. Mumma, Yana L. Radeva, Michael A. Disanti, Erika L. Gibb, Geronimo L. Villanueva

Erika Gibb

Comparison Of Townsend Dielectric Barrier Discharge In N2, N2/O2 And N2/N2o: Behavior And Density Of Radicals, F. Massines, Et. Es-Sebbar, N. Gherardi, N. Naudé, D. Tsyganov, P. Ségur, S. Pancheshnyi

Dr. Et-touhami Es-sebbar

No abstract provided.

Simulation And Analysis Of Ultrafast-Laser-Pulse-Induced Plasma Generation In Fused Silica, Jeremy Gulley, Sebastian Winkler, W. M. Dennis

Jeremy R. Gulley

Recent experiments on optical damage by ultrashort laser pulses have demonstrated that the temporal pulse shape can dramatically influence plasma generation in fused silica. We use a modified 3+1D nonlinear Schrödinger equation for the pulse propagation coupled to a rate equation for the plasma density in the dielectric material to simulate pulse propagation and plasma formation in fused silica. We use these simulations to analyze the influence of pulse shape and beam geometry on the formation of the electron plasma and hence modification in the bulk material. In particular, we simulate the effect of pulses reconstructed from experimental data. It …

Studies Of Laser Wakefield Structures And Electron Acceleration In Underdense Plasmas, Anatoly Maksimchuk, Steven A. Reed, Stepan S. Bulanov, Vladimir Chvykov, Galina Kalintchenko, Takeshi Matsuoka, Christopher Mcguffey, Gerard Mourou, Natalia Naumova, John Nees, Pascal Rousseau, Victor Yanovsky, Karl Krushelnick, Nicholas H. Matlis, Serguei Y. Kalmykov, Gennady Shvets, Michael C. Downer, C. R. Vane, J. R. Beene, Daniel W. Stracener, David R. Schultz

Serge Youri Kalmykov

Experiments on electron acceleration and optical diagnostics of laser wakes were performed on the HERCULES facility in a wide range of laser and plasma parameters. Using frequency domain holography we demonstrated single shot visualization of individual plasma waves, produced by 40 TW, 30 fs laser pulses focused to the intensity of 10^{19} W/cm^2 onto a supersonic He gas jet with plasma densities n_e ~ 10^{19} cm^{−3}. These holographic “snapshots” capture the variation in shape of the plasma wave with distance behind the driver, and resolve wave front curvature seen previously only in simulations. High-energy quasimonoenergetic electron beams were generated using …

Beam Dynamics In Pt Symmetric Optical Lattices, Konstantinos Makris, Ramy El-Ganainy, Demetrios Christodoulides, Z. Musslimani

Ramy El-Ganainy

The possibility of parity-time (PT) symmetric periodic potentials is investigated within the context of optics. Beam dynamics in this new type of optical structures is examined in detail for both one- and two- dimensional lattice geometries. It is shown that PT periodic structures can exhibit unique characteristics stemming from the nonorthogonality of the associated Floquet-Bloch modes. Some of these features include double refraction, power oscillations, and eigenfunction unfolding as well as nonreciprocal diffraction patterns.

Modeling Plasma Induced Dispersion In A Nonlinear Schrödinger Equation, Jeremy Gulley, William Dennis

Jeremy R. Gulley

Ultrafast laser pulse propagation in dielectrics is often modeled by a modified nonlinear Schrödinger equation (NLSE). At laser intensities sufficient to cause ionization, a plasma term can be included in the modified NLSE to account for free-carrier optical effects. This term is linear in the field and may be calculated from the classical Drude theory. We explore the consequences of a newly developed method for including dispersion relations of the plasma term as predicted by the Drude theory into the framework of the modified NLSE. The plasma induced dispersion terms can be shown to strongly effect ultrashort pulse evolution through …

Laboratory Experiments As Support To The Built Up Of Titan’S Theoretical Models And Interpretation Of Cassini-Huygens Data, M-C. Gazeau, Y Benilan, Et. Es-Sebbar, T. Ferradaz, E. Hébrard, A. Jolly, F. Raulin, C. Romanzin, J-C. Guillemin, C. Berteloite, A. Canosa, S. D. Le Picard, Ian R. Sims

Dr. Et-touhami Es-sebbar

No abstract provided.

Optical Solitons In Pt Periodic Potentials, Z. H. Musslimani, Konstantinos G. Makris, Ramy El-Ganainy, Demetrios N. Christodoulides

Ramy El-Ganainy

We investigate the effect of nonlinearity on beam dynamics in parity-time (PT) symmetric potentials. We show that a novel class of one- and two-dimensional nonlinear self-trapped modes can exist in optical PT synthetic lattices. These solitons are shown to be stable over a wide range of potential parameters. The transverse power flow within these complex solitons is also examined.

Solution-Processed Trilayer Inorganic Dielectric For High Performance Flexible Organic Field Effect Transistors, Hs Tan, Sr Kulkarni, T Cahyadi, Ps Lee, Sg Mhaisalkar, J Kasim, Zx Shen, F.R. Zhu

Professor ZHU, Fu Rong

No abstract provided.

Single-Cell Printing To Form Three-Dimensional Lines Of Olfactory Ensheathing Cells, Christina Othon, Xingjia Wu, Juanita Anders, Bradley Ringeisen

Christina M Othon

Biological laser printing (BioLP™) is a unique tool capable of printing high resolution two- and three-dimensional patterns of living mammalian cells, with greater than 95% viability. These results have been extended to primary cultured olfactory ensheathing cells (OECs), harvested from adult Sprague-Dawley rats. OECs have been found to provide stimulating environments for neurite outgrowth in spinal cord injury models. BioLP is unique in that small load volumes (~µLs) are required to achieve printing, enabling low numbers of OECs to be harvested, concentrated and printed. BioLP was used to form several 8 mm lines of OECs throughout a multilayer hydrogel scaffold. …

Generating Shape Invariant Potentials, Asim Gangopadhyaya

Asim Gangopadhyaya

Evolution Of Higher-Order Gray Hirota Solitary Waves, Tim Marchant

Tim Marchant

The defocusing Hirota equation has dark and gray soliton solutions which are stable on a background of periodic waves of constant amplitude. In this paper, gray solitary wave evolution for a higher-order defocusing Hirota equation is examined. A direct analysis is used to identify families of higher-order gray Hirota solitary waves, which are embedded for certain parameter values. Soliton perturbation theory is used to detmine the detailed behavior of an evolving higher-order gray Hirota solitary wave. An integral expression for the first-order correction to the wave is found and analytical expressions for the steady-state and transient components of the solitary …