Measurement of quantum weak values of photon polarization

We experimentally determine weak values for a single photon's polarization, obtained via a weak measurement that employs a two-photon entangling operation, and postselection. The weak values cannot be explained by a semiclassical wave theory, due to the two-photon entanglement. We observe the variation in the size of the weak value with measurement strength, obtaining an average measurement of the S-1 Stokes parameter more than an order of magnitude outside of the operator's spectrum for the smallest measurement strengths.

General foundation for the nonlinear ponderomotive four-force in laser-plasma interactions

The interaction of electromagnetic radiation with plasmas is studied in relativistic four-vector formalism. A gauge and Lorentz invariant ponderomotive four-force is derived from the time dependent nonlinear three-force of Hora (1985). This four-force, due to its Lorentz invariance, contains new magnetic field terms. A new gauge and Lorentz invariant model of the response of plasma to electromagnetic radiation is then devised. An expression for the dispersion relation is obtained from this model. It is then proved that the magnetic permeability of plasma is unity for a general reference frame. This is an important result since it has been previously assumed in many plasma models.

Mode-locked semiconductor lasers with optical injection

We perform characterization of the pulse shape and noise properties of quantum dot passively mode-locked lasers (PMLLs). We propose a novel method to determine the RF linewidth and timing jitter, applicable to high repetition rate PMLLs, through the dependence of modal linewidth on the mode number. Complex electric field measurements show asymmetric pulses with parabolic phase close to threshold, with the appearance of waveform instabilities at higher currents. We demonstrate that the waveform instabilities can be overcome through optical injection-locking to the continues wave (CW) master laser, leading to time-bandwidth product (TBP) improvement, spectral narrowing, and spectral tunability. We discuss the benefits of single- and dual-tone master sources and demonstrate that dual-tone optical injection can additionally improve the noise properties of the slave laser with RF linewidth reduction below instrument limits (1 kHz) and integrated timing jitter values below 300 fs. Dual-tone injection allowed slave laser repetition rate control over a 25 MHz range with reduction of all modal optical linewidths to the master source linewidth, demonstrating phase-locking of all slave modes and coherence improvement.

Data Protection and Packet Mode in the Distributed Information Measurement and Control System for Research in Physics

The present paper is devoted to creation of cryptographic data security and realization of the packet mode in the distributed information measurement and control system that implements methods of optical spectroscopy for plasma physics research and atomic collisions. This system gives a remote access to information and instrument resources within the Intranet/Internet networks. The system provides remote access to information and hardware resources for the natural sciences within the Intranet/Internet networks. The access to physical equipment is realized through the standard interface servers (PXI, C������C, and GPIB), the server providing access to Ethernet devices, and the communication server, which integrates the equipment servers into a uniform information system. The system is used to make research task in optical spectroscopy, as well as to support the process of education at the Department of Physics and Engineering of Petrozavodsk State University.

Leveraging Existing Plasma Simulation Codes

This paper describes the process of wrapping existing scientific codes in the domain of plasma physics simulations through the use of the Sun���s Java Native Interface. We have created a Java front-end for a particular functionality, offered by legacy native libraries, in order to achieve reusability and interoperability without having to rewrite these libraries. The technique, introduced in this paper, includes two approaches ��� the one-to-one mapping for wrapping a number of native functions, and using peer classes for wrapping native data structures.

Driving Flows in Laboratory Astrophysical Plasma Jets: The Mochi.LabJet Experiment

Thesis (Master's)--University of Washington, 2016-08

3D Ionospheric Effects on HF Propagation and Heating

The thesis uses a three-dimensional, first-principles model of the ionosphere in combination with High Frequency (HF) raytracing model to address key topics related to the physics of HF propagation and artificial ionospheric heating. In particular: 1. Explores the effect of the ubiquitous electron density gradients caused by Medium Scale Traveling Ionospheric Disturbances (MSTIDs) on high-angle of incidence HF radio wave propagation. Previous studies neglected the all-important presence of horizontal gradients in both the cross- and down-range directions, which refract the HF waves, significantly changing their path through the ionosphere. The physics-based ionosphere model SAMI3/ESF is used to generate a self-consistently evolving MSTID that allows for the examination of the spatio-temporal progression of the HF radio waves in the ionosphere. 2. Tests the potential and determines engineering requirements for ground- based high power HF heaters to trigger and control the evolution of Equatorial Spread F (ESF). Interference from ESF on radio wave propagation through the ionosphere remains a critical issue on HF systems reliability. Artificial HF heating has been shown to create plasma density cavities in the ionosphere similar to those that may trigger ESF bubbles. The work explores whether HF heating may trigger or control ESF bubbles. 3. Uses the combined ionosphere and HF raytracing models to create the first self-consistent HF Heating model. This model is utilized to simulate results from an Arecibo experiment and to provide understanding of the physical mechanism behind observed phenomena. The insights gained provide engineering guidance for new artificial heaters that are being built for use in low to middle latitude regions. In accomplishing the above topics: (i) I generated a model MSTID using the SAMI3/ESF code, and used a raytrace model to examine the effects of the MSTID gradients on radio wave propagation observables; (ii) I implemented a three- dimensional HF heating model in SAMI3/ESF and used the model to determine whether HF heating could artificially generate an ESF bubble; (iii) I created the first self-consistent model for artificial HF heating using the SAMI3/ESF ionosphere model and the MoJo raytrace model and ran a series of simulations that successfully modeled the results of early artificial heating experiments at Arecibo.

High Precision Plasma Etch for Pattern Transfer: Towards Fluorocarbon Based Atomic Layer Etching

A basic requirement of a plasma etching process is fidelity of the patterned organic materials. In photolithography, a He plasma pretreatment (PPT) based on high ultraviolet and vacuum ultraviolet (UV/VUV) exposure was shown to be successful for roughness reduction of 193nm photoresist (PR). Typical multilayer masks consist of many other organic masking materials in addition to 193nm PR. These materials vary significantly in UV/VUV sensitivity and show, therefore, a different response to the He PPT. A delamination of the nanometer-thin, ion-induced dense amorphous carbon (DAC) layer was observed. Extensive He PPT exposure produces volatile species through UV/VUV induced scissioning. These species are trapped underneath the DAC layer in a subsequent plasma etch (PE), causing a loss of adhesion. Next to stabilizing organic materials, the major goals of this work included to establish and evaluate a cyclic fluorocarbon (FC) based approach for atomic layer etching (ALE) of SiO2 and Si; to characterize the mechanisms involved; and to evaluate the impact of processing parameters. Periodic, short precursor injections allow precise deposition of thin FC films. These films limit the amount of available chemical etchant during subsequent low energy, plasma-based Ar+ ion bombardment, resulting in strongly time-dependent etch rates. In situ ellipsometry showcased the self-limited etching. X-ray photoelectron spectroscopy (XPS) confirms FC film deposition and mixing with the substrate. The cyclic ALE approach is also able to precisely etch Si substrates. A reduced time-dependent etching is seen for Si, likely based on a lower physical sputtering energy threshold. A fluorinated, oxidized surface layer is present during ALE of Si and greatly influences the etch behavior. A reaction of the precursor with the fluorinated substrate upon precursor injection was observed and characterized. The cyclic ALE approach is transferred to a manufacturing scale reactor at IBM Research. Ensuring the transferability to industrial device patterning is crucial for the application of ALE. In addition to device patterning, the cyclic ALE process is employed for oxide removal from Si and SiGe surfaces with the goal of minimal substrate damage and surface residues. The ALE process developed for SiO2 and Si etching did not remove native oxide at the level required. Optimizing the process enabled strong O removal from the surface. Subsequent 90% H2/Ar plasma allow for removal of C and F residues.

An��lisis te��rico del contacto plasma-superficie y sus aplicaciones industriales

Actualmente, la f��sica de plasmas constituye una parte importante de la investigaci��n en f��sica que est�� siendo desarrollada. Su campo de aplicaci��n var��a desde el estudio de plasmas interestelares y c��smicos, como las estrellas, las nebulosas, el medio intergal��ctico, etc.; hasta aplicaciones m��s terrenales como la producci��n de microchips o los dispositivos de iluminaci��n. Resulta particularmente interesante el estudio del contacto de una superficie met��lica con un plasma. Siendo la raz��n que, la din��mica de la interfase formada entre un plasma imperturbado y una superficie met��lica, resulta de gran importancia cuando se trata de estudiar problemas como: la implantaci��n i��nica en una oblea de silicio, el grabado por medio de plasmas, la carga de una aeronave cuando atraviesa la ionosfera y la diagnosis de plasmas mediante sondas de Langmuir. El uso de las sondas de Langmuir est�� extendido a trav��s de multitud de aplicaciones tecnol��gicas e industriales como m��todo de diagnosis de plasmas. Algunas de estas aplicaciones han sido mencionadas justo en el p��rrafo anterior. Es m��s, su uso tambi��n es muy popular en la investigaci��n en f��sica de plasmas, por ser una de las pocas t��cnicas de diagnosis que proporciona informaci��n local sobre el plasma. El equipamiento donde es habitualmente implementado var��a desde plasmas de laboratorio de baja temperatura hasta plasmas de fusi��n en dispositivos como tokamaks o stellerators. La geometr��a m��s popular de este tipo de sondas es cil��ndrica, y la principal magnitud que se usa para diagnosticar el plasma es la corriente recogida por la sonda cuando se encuentra polarizada a un cierto potencial. Existe un interes especial en diagnosticar por medio de la medida de la corriente i��nica recogida por la sonda, puesto que produce una perturbaci��n muy peque��a del plasma en comparaci��n con el uso de la corriente electr��nica. Dada esta popularidad, no es de extra��ar que grandes esfuerzos se hayan realizado en la consecuci��n de un modelo te��rico que explique el comportamiento de una sonda de Langmuir inmersa en un plasma. Hay que remontarse a la primera mitad del siglo XX para encontrar las primeras teor��as que permiten diagnosticar par��metros del plasma mediante la medida de la corriente i��nica recogida por la sonda de Langmuir. Desde entonces, las mejoras en estos modelos y el desarrollo de otros nuevos ha sido una constante en la investigaci��n en f��sica de plasmas. No obstante, todav��a no est�� claro como los iones se aproximan a la superficie de la sonda. Las dos principales, a la par que opuestas, aproximaciones al problema que est��n ampliamente aceptadas son: la radial y la orbital; siendo el problema que ambas predicen diferentes valores para la corriente i��nica. Los experimentos han arrojado resultados de acuerdo con ambas teor��as, la radial y la orbital; y lo que es m��s importante, una transici��n entre ambos ha sido recientemente observada. La mayor��a de los logros conseguidos a la hora de comprender como los iones caen desde el plasma hacia la superficie de la sonda, han sido llevados a cabo en el campo de la din��mica de fluidos o la teor��a cin��tica. Por otra parte, este problema puede ser abordado mediante el uso de simulaciones de part��culas. La principal ventaja de las simulaciones de part��culas sobre los modelos de fluidos o cin��ticos es que proporcionan mucha m��s informaci��n sobre los detalles microsc��picos del movimiento de las part��culas, adem��s es relativamente f��cil introducir interacciones complejas entre las part��culas. No obstante, estas ventajas no se obtienen gratuitamente, ya que las simulaciones de part��culas requieren grand��simos recursos. Por esta raz��n, es pr��cticamente obligatorio el uso de t��cnicas de procesamiento paralelo en este tipo de simulaciones. El vac��o en el conocimiento de las sondas de Langmuir, es el que motiva nuestro trabajo. Nuestra aproximaci��n, y el principal objetivo de este trabajo, ha sido desarrollar una simulaci��n de part��culas que nos permita estudiar el problema de una sonda de Langmuir inmersa en un plasma y que est�� negativamente polarizada con respecto a ��ste. Dicha simulaci��n nos permitir��a estudiar el comportamiento de los iones en los alrededores de una sonda cil��ndrica de Langmuir, as�� como arrojar luz sobre la transici��n entre las teor��as radiales y orbitales que ha sido observada experimentalmente. Justo despu��s de esta secci��n introductoria, el resto de la tesis est�� dividido en tres partes tal y como sigue: La primera parte est�� dedicada a establecer los fundamentos te��ricos de las sondas de Langmuir. En primer lugar, se realiza una introducci��n general al problema y al uso de sondas de Langmuir como m��todo de diagnosis de plasmas. A continuaci��n, se incluye una extensiva revisi��n bibliogr��fica sobre las diferentes teor��as que proporcionan la corriente i��nica recogida por una sonda. La segunda parte est�� dedicada a explicar los detalles de las simulaciones de part��culas que han sido desarrolladas a lo largo de nuestra investigaci��n, as�� como los resultados obtenidos con las mismas. Esta parte incluye una introducci��n sobre la teor��a que subyace el tipo de simulaciones de part��culas y las t��cnicas de paralelizaci��n que han sido usadas en nuestros c��digos. El resto de esta parte est�� dividido en dos cap��tulos, cada uno de los cuales se ocupa de una de las geometr��as consideradas en nuestras simulaciones (plana y cil��ndrica). En esta parte discutimos tambi��n los descubrimientos realizados relativos a la transici��n entre el comportamiento radial y orbital de los iones en los alrededores de una sonda cil��ndrica de Langmuir. Finalmente, en la tercera parte de la tesis se presenta un resumen del trabajo realizado. En este resumen, se enumeran brevemente los resultados de nuestra investigaci��n y se han incluido algunas conclusiones. Despu��s de esto, se enumeran una serie de perspectivas futuras y extensiones para los c��digos desarrollados.

Evaluation of vinylidene fluoride polymers for use in space environments : comparison of radiation sensitivities

Poly(vinylidene fluoride) and copolymers of vinylidene fluoride with hexafluoropropylene, trifluoroethylene and chlorotrifluoroethylene have been exposed to gamma irradiation in vacuum, up to doses of 1MGy under identical conditions, to obtain a ranking of radiation sensitivities. Changes in the tensile properties, crystalline melting points,heats of fusion, gel contents and solvent uptake factors were used as the defining parameters. The initial degree of crystallinity and film processing had the greatest influence on relative radiation damage, although the cross-linked network features were almost identical in their solvent swelling characteristics, regardless of the comonomer composition or content.

Polymersomes, smaller than you think : ferrocene as a TEM probe to determine core structure

By incorporating ferrocene into the hydrophobic membrane of PEG-b-PCL polymersome nanoparticles it is possible to selectively visualize their core using Transmission Electron Microscopy (TEM). Two different sizes of ferrocene-loaded polymersomes with mean hydrodynamic diameters of approximately 40 and 90 nm were prepared. Image analysis of TEM pictures of these polymersomes found that the mean diameter of the core was 4���5 times smaller than the mean hydrodynamic diameter. The values obtained also allow the surface diameter and internal volume of the core to be calculated.

A solid state Marx generator with a novel configuration

The new configuration proposed in this paper for Marx Generator (MG.) aims to generate high voltage for pulsed power applications through reduced number of semiconductor components with a more efficient load supplying process. The main idea is to charge two groups of capacitors in parallel through an inductor and take the advantage of resonant phenomenon in charging each capacitor up to a double input voltage level. In each resonant half a cycle, one of those capacitor groups are charged, and eventually the charged capacitors will be connected in series and the summation of the capacitor voltages can be appeared at the output of the topology. This topology can be considered as a modified Marx generator which works based on the resonant concept. Simulated models of this converter have been investigated in Matlab/SIMULINK platform and the acquired results fully satisfy the anticipations in proper operation of the converter.