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  • Undergraduate Poster Abstracts
  • Physics (Except Biophysics)

    THU-915 MAGNETIC CONFINEMENT TIME CALCULATION FOR CHARGED PARTICLES IN MULTIPOLAR STATIC MAGNETIC FIELDS IN MIRROR AND CUSP CONFIGURATION

    • Alberto Guadalupe ;
    • Ernesto Ulloa ;

    THU-915

    MAGNETIC CONFINEMENT TIME CALCULATION FOR CHARGED PARTICLES IN MULTIPOLAR STATIC MAGNETIC FIELDS IN MIRROR AND CUSP CONFIGURATION

    Alberto Guadalupe, Ernesto Ulloa.

    Polytechnic University of Puerto Rico, San Juan, PR.

    The study of charged particles in multi-polar static magnetic fields is based on the particle trajectory to calculate the confinement time of a group of particles in a specific position using the classical Newtonian dynamics method. The experimental setup comprises arrangements of 4 and 6 coils, working in mirror and cusp configurations. This is done through 2 simulations. The first simulation generates the magnetic field with the number of coils defined by the user. The user is able to set the current, radius, position, and angle of orientation in X and Y axes of each coil. Then, the generated magnetic field data is loaded into a second program that calculates the trajectory of each particle as it travels through the magnetic field and its confinement time. This second program allows the user to determine the number of particles that are going to be evaluated. The program calculates the position and the velocity of the particles in order to plot the particle trajectory and computes their confinement time. The time confinement shows significant variations when alternating the coil configurations. The time confinement for a pair of coils in mirror configuration is an order value larger when compared to configurations of mirror and cusp with multiple coils.

    THU-909 REANALYSIS OF THE SAVANNAH RIVER REACTOR ANTINEUTRINO EXPERIMENT

    • Patricia Kobak ;
    • David Ernst ;

    THU-909

    REANALYSIS OF THE SAVANNAH RIVER REACTOR ANTINEUTRINO EXPERIMENT

    Patricia Kobak1, David Ernst2.

    1Brigham Young University-Idaho, Rexburg, ID, 2Vanderbilt University, Nashville, TN.

    The standard model of particle physics contains 3 types, called flavors, of neutrinos: electron, muon, and tau. Sixteen experiments in the 1980's and 1990's measured the neutrino flux from nuclear reactors and found the flux measured divided by the theoretical flux to be 0.976 +/-0.03, a result consistent with 1. A recent updated calculation of this neutrino flux alters this ratio to 0.943 +/- 0.03, a number less than 1. A recent article by Mention et al., proposed the existence of a 4th neutrino with a larger mass than the 3 known neutrinos and interacting more weakly than the 3 known neutrinos. For our summer project, we focused on one of these experiments, the Savannah River Project experiment. Our task was to create a computer model of this reactor such that the results would reproduce accurately the results of the experimentalists when using the 2-neutrino approximation that they employed. This would validate our model. We would then change the flux to its new value, change the analysis to a more physical 4-neutrino model, and combine it with 4 neutrino models of all existing neutrino oscillation experiments to see whether or not the existing data are in accord with the 4 neutrino hypothesis. We were not successful this summer at producing a sufficiently accurate model of the Savannah River Project experiment, but we will finish this first analysis and continue to analyze additional similar reactor experiments.

    FRI-916 SPECTROSCOPIC AND MAGNETIC PROPERTIES OF NEODYMIUM DOPED IN GDPO4 NANOSTARS PREPARED BY SOLVOTHERMAL METHOD

    • Nicolas Balli ;
    • Ajith Kumar ;
    • Dhiraj Sardar ;

    FRI-916

    SPECTROSCOPIC AND MAGNETIC PROPERTIES OF NEODYMIUM DOPED IN GDPO4 NANOSTARS PREPARED BY SOLVOTHERMAL METHOD

    Nicolas Balli, Ajith Kumar, Dhiraj Sardar.

    The University of Texas at San Antonio, San Antonio, TX.

    Neodymium-doped gadolinium orthophosphate (GdPO4:Nd3+) luminomagnetic nanostars were prepared by a solvothermal method using metal nitrates and phosphoric acid. Monoclinic 6-lobed nanostars with 600 nm length were obtained with uniform particle size distribution. After heat-treatment at 800 °C for 1 hour in air, the GdPO4:Nd3+ sample showed characteristic emission bands of Nd3+ with the strongest emission at 1,064 nm. The emission intensity and fluorescence decay time are dependent upon the Nd3+ concentration with the highest emission intensity and longest fluorescence decay lifetime of 311 µs at 1,064 nm with 0.5 mol% Nd3+. Under 808 nm excitation with 12 W/cm2 power density, we obtained a quantum yield of 9% for the 1.0 mol% Nd3+. The presence of paramagnetic Gd3+ exhibits magnetic properties, giving the nanostars a calculated magnetic moment of 1,510 and 107,965 Bohr magneton at 300 K and 5 K, respectively.

    FRI-913 INSTRUMENTATION OF A SELF-CORRECTING DATA ACQUISITION SYSTEM FOR ULTRAFAST LASERS

    • Fabricio Marin ;
    • Eric Landahl ;

    FRI-913

    INSTRUMENTATION OF A SELF-CORRECTING DATA ACQUISITION SYSTEM FOR ULTRAFAST LASERS

    Fabricio Marin, Eric Landahl.

    DePaul University, Chicago, IL.

    Optical phenomena in semiconductors and other light-sensitive materials typically happen for very short time durations and require instruments capable of measuring nanosecond to femtosecond time resolutions. Electronics clocking in the gigahertz range can only measure nanosecond time lengths, and it is expensive and difficult to get research time at national laboratories. The purpose of this research project is to design a system capable of achieving variable time delays up to the femtosecond range to use in pump-probe experiments in order to study brief optical phenomenon in semiconductors and other materials. The time delay is achieved using a delay stage driven by a micro stepper which moves in variable increments while an encoder counts the steps and tells a computer to makes adjustments as necessary. This requires developing software using machine code to communicate between electronics connected to a raspberry pi and the stepper motor. Results show that the system is limited by the number of frames the encoder can count per full step which yields roughly 100 femtosecond resolution at 1/25th of a step and 2,400 femtoseconds per full step. Materials are yet to be tested but are predicted to exhibit other optical properties when analyzed at the femtosecond time range. A relatively inexpensive and programmable setup like this can be used to study optical phenomenon such as reflectivity, absorption, transmission, or polarization in semiconductors as well as other light-sensitive materials.

    FRI-917 INVESTIGATING QUANTUM DOT SELF ASSEMBLY IN A CHOLESTERIC LIQUID CRYSTAL

    • Kyle Kabasares ;
    • Linda Hirst ;

    FRI-917

    INVESTIGATING QUANTUM DOT SELF ASSEMBLY IN A CHOLESTERIC LIQUID CRYSTAL

    Kyle Kabasares, Linda Hirst.

    University of California, Merced, Merced, CA.

    An ongoing goal in condensed matter physics is directly controlling the self assembly of quantum dots (QDs) into specific structures while maintaining their original electronic and optical properties. One method of controlling the self assembly of QDs is to disperse them within a liquid crystal (LC) medium and apply a variety of thermal stimulations. Recently, our lab developed a method of creating spherical, vesicle-shaped QDs within a nematic LC. Vesicle formation depends on the QD concentration in the LC as well as the LC’s intermolecular dispersion forces and thermal properties. In this project, we investigated the dispersion of CdSe/ZnS (core/shell) QDs in a cholesteric LC (CLC) medium and predicted the QD aggregations to cluster near the LC defects. By varying parameters such as QD concentration and temperature, we exploited the CLC's sensitive optical and thermal properties. To observe these effects, we applied spectrophotometry, polarized optical microscopy, and fluorescence microscopy. These techniques highlighted the aggregation of QDs within the host CLC and identified how LC-phase transitions determine where QD aggregates form. This work illustrates the possibility of new LC-based QD devices, and we will continue by exploring the lasing potential of our sample.

    FRI-912 LONG RANGE PRESSURE GRADIENTS IN SUBSURFACE FLOWS INVOLVING GRANULAR MATERIALS

    • Jesse Rodriguez ;
    • Juan Restrepo ;

    FRI-912

    LONG RANGE PRESSURE GRADIENTS IN SUBSURFACE FLOWS INVOLVING GRANULAR MATERIALS

    Jesse Rodriguez, Juan Restrepo.

    Oregon State University, Corvallis, OR.

    Observational evidence indicates that long range transverse drying events are possible when a steady stress is applied to the surface of saturated granular media. This phenomenon is easy to recreate by applying a steady point-stress to wet sand, resulting in the draining of water near the exposed surface over unusually large expanses. This long range phenomenon cannot be explained without assuming heterogeneity in the pearmability; however, the beach sand, where this observation is made, is essentially homogeneous. In this analytical study we develop a theoretical framework that explains this conundrum. The theoretical estimates are confirmed by computation. An understanding of this mechanism has potential consequences regarding and applications to filtration and subsurface pollutant transport in stressed granular media.

    THU-916 COMPUTATIONAL MODELING OF SHORT BASELINE NEUTRINO OSCILLATION EXPERIMENTS AND A SEARCH FOR THE EXISTENCE OF A FOURTH NEUTRINO

    • John Vastola ;
    • David Ernst ;

    THU-916

    COMPUTATIONAL MODELING OF SHORT BASELINE NEUTRINO OSCILLATION EXPERIMENTS AND A SEARCH FOR THE EXISTENCE OF A FOURTH NEUTRINO

    John Vastola, David Ernst.

    1University of Central Florida, Orlando, FL, 2Vanderbilt University, Nashville, TN.

    Neutrino oscillations, one flavor of neutrino can later be measured as another flavor with some probability, lie outside the purview of the standard model of particle physics, and thus represent an exciting frontier that is currently poorly understood. Short baseline reactor experiments conducted in the 1980s and 1990s were consistent with no oscillations, contradicting contemporary higher precision experiments by Daya Bay and T2K, among others. This suggests that their analyses were flawed. Mention et al., assert that a 3.5% increase in the flux of neutrinos in these experiments due to revised reactor antineutrino spectra of 235U, 239Pu, 241Pu, and 238U can partially account for this discrepancy. It is also believed that a 3, or perhaps 4, neutrino model will better fit experimental data. To test these hypotheses, we have constructed a computational model of 6 short baseline experiments and reproduced their results to within reasonable accuracy. We hope to make the aforementioned adjustments to our model and analyze how they change our results.

    FRI-914 RADIATIVE ENERGY LOSS BY RELATIVISTIC ELECTRONS IN THE PRESENCE OF A STATIC MAGNETIC FIELD AND OSCILLATING ELECTRIC FIELD AT THE ELECTRON CYCLOTRON RESONANCE

    • Mario Acevedo-Portela ;
    • Juan Chang-Liang ;
    • Joel Arocho-Rivera ;
    • Carola Cruz-Molina ;

    FRI-914

    RADIATIVE ENERGY LOSS BY RELATIVISTIC ELECTRONS IN THE PRESENCE OF A STATIC MAGNETIC FIELD AND OSCILLATING ELECTRIC FIELD AT THE ELECTRON CYCLOTRON RESONANCE

    Mario Acevedo-Portela, Juan Chang-Liang, Joel Arocho-Rivera, Carola Cruz-Molina.

    Polytechnic University of Puerto Rico, San Juan, PR.

    In particle orbit theory, charges interacting with electromagnetic fields may accelerate to very high speeds by virtue of the Lorentz force. Often particles can attain speeds that are comparable to that of light, and with it relativistic effects come into play. However, the Lorentz force does not account for the radiation reaction by the electron’s self-field as it accelerates through the applied electromagnetic field. This can potentially affect the dynamics of the system. The objective of this investigation is to study the observable effects of particle trajectories in the relativistic regime with the inclusion of the radiation reaction. A classically based particle kinematics MATLAB code was modified to implement relativistic corrections in order to attain reliable numerical approximations of single particle motion subject to static non-uniform magnetic fields and time varying electric fields. As part of the particle trajectory simulation, the radiation loss back-reaction was added to the force calculated from the ambient electric and magnetic fields at each step in the simulation. Verification that radiation loss was present was calculated using the Lienard generalization of the Larmor formula. Electron cyclotron resonance accelerations were studied for a static magnetic field and a resonating electric field. Our results suggest that at relativistic speeds, the dynamics of the particle are highly dominated by relativistic effects; however, the radiation back-reaction had little influence over the motion of the particle. Relativistic single particle motion lays the foundation for multi-particle systems for macroscopic groups of charges to simulate collective behavior of ion populations in plasma.

    THU-917 INTRACELLULAR IMAGING APPLICATIONS OF RARE EARTH DOPED MULTIFUNCTIONAL METAL OXYSULPHIDE NANOMATERIALS

    • Julio Avalos ;
    • Ajith Kumar ;
    • L. Chris Mimun ;
    • Francisco Pedraza III ;
    • Dhiraj Sardar ;

    THU-917

    INTRACELLULAR IMAGING APPLICATIONS OF RARE EARTH DOPED MULTIFUNCTIONAL METAL OXYSULPHIDE NANOMATERIALS

    Julio Avalos, Ajith Kumar, L. Chris Mimun, Francisco Pedraza III, Dhiraj Sardar.

    The University of Texas at San Antonio, San Antonio, TX.

    Nanomaterials with multiple imaging features have drawn a lot of attention in the medical industry, where there is always a high demand for contrast agents to provide more information about intracellular level mechanisms. Rare-earth doped inorganic nanophosphors are the best choice for these applications due to several advantages including excellent optical properties, size, composition control, etc. In this work, we present a series of rare-earth doped metal oxysulphide hosts, M2O2S:Re (M = Gd,Y, Re=Yb,Er,Eu), as an alternate host with fluorescence efficiency equal or even higher than that of halides. Nanoparticles with sizes ranging from 20 - 200 nm were synthesized by thermal decomposition and homogeneous precipitation and were characterized by various techniques including X-ray diffraction, electron microscopy, optical absorption, and emission and magnetization experiments. Confocal imaging was done to confirm the internalization of the nanoparticles inside the cells. In vitro and in vivo animal imaging experiments show possible applications of this material in infrared optical imaging applications. Furthermore, magnetic imaging experiments show that the proposed material can also be used as a magnetic contrast agent in magnetic imaging applications. We conclude that the proposed material could find potential applications as a multimodal contrast agent in biomedical imaging. [This research was funded by the National Science Foundation Partnerships for Research and Education in Materials (NSF-PREM) grant N0-DMR-0934218 and by NIH/NIGMS MARC U*STAR GM07717.]

    FRI-915 STATISTICAL PROPERTIES OF DARK MATTER HALOS IN FAST PARTICLE MESH SIMULATIONS

    • Jaime Sahagun ;
    • Uros Seljak ;
    • Yu Feng ;

    FRI-915

    STATISTICAL PROPERTIES OF DARK MATTER HALOS IN FAST PARTICLE MESH SIMULATIONS

    Jaime Sahagun1, Uros Seljak, Yu Feng.

    University of California, Berkeley, Berkeley, CA.

    One of the bottlenecks in studying the halo formation and large-scale structure of the universe is the n-body simulations, which typically run for days on a supercomputer, making it a very expensive process. The fast particle mesh (fastPM) method significantly reduces the computation time (to < 1%) by marginalizing the small-scale dynamics below the size scale of a typical halo. We investigate the statistical properties of halos in fastPM as we decrease the number of time steps used in fastPM from 20 to 3. We compare the bias of dark matter halos at different mass bins to N-body simulations. We also measured the cross power spectrum of the dark matter halos between fastPM mocks and n-body simulations. We show that the halos in a 5-step fastPM mock correlate with those from the corresponding n-body simulation at k > 1 h/Mpc at a 90% level. These mocks also reproduce the bias of an n-body simulation. The fastPM mocks will allow us to study the statistical properties of the universe’s mass distribution more effectively and efficiently in many aspects of cosmology, such as understanding theoretical models of halo formation, optimizing survey designs, and propagation of error through complex analysis chains.

    THU-912 CHARGE TRANSFER AND STRUCTURAL DEFORMATION OF MULTI-CYCLED ELECTROCHEMICALLY INTERCALATED GRAPHITE

    • Erick Garcia ;
    • Jared Lodico ;
    • Edward White ;
    • William Hubbard ;
    • Brian Zutter ;
    • BC Regan ;

    THU-912

    CHARGE TRANSFER AND STRUCTURAL DEFORMATION OF MULTI-CYCLED ELECTROCHEMICALLY INTERCALATED GRAPHITE

    Erick Garcia1, Jared Lodico1, Edward White2, William Hubbard1, Brian Zutter1, BC Regan1.

    1University of California, Los Angeles, Los Angeles, CA, 2Imperial College London, London, GB.

    Many batteries use graphitic electrodes that form graphite intercalation compounds (GICs) as part of normal operation. GICs are created when foreign molecules (intercalants) are inserted between the layers of a host graphite. A common battery failure mode is damaged electrodes from this repeated intercalation. The number of graphene layers between each full layer of intercalant determines the GIC’s stage number. The stage transition process is currently best modeled by the Daumas-Herold (DH) theory. The DH theory describes intercalants as islands that are free to move and rearrange within the host, as opposed to classical theory where intercalants enter the host in complete layers. However, the DH theory does not sufficiently capture the activities present during stage transitions at the microscopic level. Here, we image graphite’s structural changes that occur during intercalation, while simultaneously measuring its associated charge transfer and stage transitions. This analysis is done to understand the optimal conditions for prolonged performance of GICs. A potentiostat is used to perform cyclic voltammetry and electrochemically intercalate graphite in 96% sulfuric acid (H2SO4). The graphite is cycled from the open circuit potential of approximately 0 V to 0.9 V relative to the reference electrode. Preliminary findings suggest that structural changes align with expected charge transfer from the cyclic voltammetry. The understanding of the structural changes within the graphite, along with the associated charge transfer that occurs during stage transitions, can be a step forward towards improved modern battery technologies.

    THU-913 DETECTING LOW ENERGY AXIONS WITH DARK MATTER EXPERIMENTS

    • Hector Carranza Jr. ;
    • Gray Rybka ;
    • Leslie Rosenberg ;

    THU-913

    DETECTING LOW ENERGY AXIONS WITH DARK MATTER EXPERIMENTS

    Hector Carranza Jr.1, Gray Rybka2, Leslie Rosenberg2.

    1California State University Dominguez Hills, Carson, CA, 2University of Washington, Seattle, WA.

    Axions are a hypothetical particle predicted in nuclear physics that could also be the main component of the dark matter seen in many astrophysical measurements. Experiments such as the axion dark matter experiment (ADMX) are underway to search for dark matter axions through their conversion into microwave photons inside an RF cavity. The hot plasma in the sun would also be a source of axions. The CERN Axion Solar Telescope (CAST) and other such experiments have been made to detect high-energy solar axions. However, low energy axions produced by photon conversion in the sun may remain gravitationally bound in the solar system and build up over time. If the local density of these solar produced axions is comparable to dark matter, then ADMX would also be sensitive to them. We estimate the density of solar produced, gravitationally bound axions and axion-like-particles at earth with 2 simple models of axions produced from thermal photons in the sun. One is an optimistic model where the energy loss of the sun from axion-like particles is as large as allowed by current solar observations, and the other is a QCD-axion inspired model. We also examine the difference in signal between dark matter axions and solar produced axions.

    FRI-909 OPTIMIZATION OF HEXAGONAL BORON NITRIDE FOR 2D ELECTRONICS

    • Lakshika Ruwanpathirana ;
    • Matt Gilbert ;

    FRI-909

    OPTIMIZATION OF HEXAGONAL BORON NITRIDE FOR 2D ELECTRONICS

    Lakshika Ruwanpathirana1, Matt Gilbert2.

    1 School of Mathematics, Pierce College, Woodland Hills, CA, 2University of California, Berkeley, Berkeley, CA.

    The 2-dimensional insulator hexagonal boron nitride (hBN) has been highly researched for its exceptional thermal conductivity, high tensile strength (Young’s modulus equivalent to diamond), and isostructural characteristics with graphene. However, the optimal parameters for synthesis by chemical vapor deposition (CVD) have never been fully understood or recorded. During the Transfer-to-Excellence Research Experience for Undergraduates (TTE REU) 2015 Summer Program, we studied the CVD of hBN to understand how varying precursor temperature can affect the growth of hBN. We characterize our hBN using Raman spectroscopy and scanning electronic microscopy (SEM) to observe its size, percent coverage, and number of layers. This research represents significant progress to optimize the precursor temperature for high quality, full coverage, large scale hexagonal boron nitride for potential 2D nanoelectronics and other 2D nanodevices.

    FRI-908 IMAGE CALIBRATION BASED ON RAYLEIGH SCATTER IN SIO2

    • Erik Muñiz ;
    • Joshua Smith ;
    • Fabian Magana-Sandoval ;

    FRI-908

    IMAGE CALIBRATION BASED ON RAYLEIGH SCATTER IN SIO2

    Erik Muñiz, Joshua Smith, Fabian Magana-Sandoval.

    California State University, Fullerton, Fullerton, CA.

    The Laser Interferometer Gravitational-wave Observatory (LIGO) is a major project designed to directly measure gravitational waves from the cosmos. Increasing the astrophysical range of the LIGO detectors requires the use of state-of-the-art optics with as little scattering as possible. Using a custom-built imaging scatterometer, we measured the scattered light from a high quality fused silica viewport of the type used in LIGO. We found that the total scattering of the front and back surfaces was less than the scattering in the substrate material. We hypothesized that the origin of the substrate scattering was Rayleigh scattering, like the atmospheric scattering that makes the sky blue. Here we report the characteristics of scatter in our fused silica sample and compare it to theory and the measured scattering values in the literature. We measured the maximum scattered light intensity ratio to be about 0.5 ppm cm-1 at 1,064 nm, which agrees with the theoretical value for Rayleigh scattering in fused silica. We also confirmed that the substrate scattering exhibits a cos2 polarization angle dependence in accordance with Rayleigh scattering law. We conclude that the bulk scattering we observed is Rayleigh scattering and that this sets a fundamental limit to the total scattering in fused silica viewports.

    FRI-900 OPTICAL PROPERTIES OF NIOBIUM- AND TANTALUM-DOPED VANADIUM DIOXIDE THIN FILMS

    • Ama Agyapong ;
    • Tanviben Patel ;
    • Victor Adedeji ;

    FRI-900

    OPTICAL PROPERTIES OF NIOBIUM- AND TANTALUM-DOPED VANADIUM DIOXIDE THIN FILMS

    Ama Agyapong, Tanviben Patel, Victor Adedeji.

    Elizabeth City State University, Elizabeth City, NC.

    Prior research shows that vanadium dioxide (VO2) undergoes reversible structural changes causing it to be spectrally selective at around 68 °C. The purpose of this research is to explore the spectral selectiveness of VO2 by incorporating a small amount of niobium (Nb) and tantalum (Ta) in the samples. These transition metals are larger than the vanadium in VO2 thin films and influence the magnitude of the change during optical properties switching and the corresponding transition temperatures as well. The samples were prepared by DC magnetron sputtering of vanadium metal and RF co-sputtering of the transition metal impurities. The metals were deposited on quartz substrates and subsequently annealed at a temperature of 500 °C in a pure oxygen and nitrogen gas mixture for 4 hours at a pressure of 800 mTorr to produce VO2 with the impurities. The reflectance and transmittance data of the samples were acquired under varying sample temperatures: from room temperature to about 90 °C and back to room temperature. Results showing the variation of reflectance and transmittance with temperature are reported. SEM images show the surface morphology of the as-deposited samples and oxidized samples. EDX data gave the atomic composition of the films before and after oxidation. Surface chemical composition mapping indicates the uniformity of the samples.

    THU-900 BIMETALLIC NANOSTARS AND THEIR EFFECTS IN SURFACE-ENHANCED RAMAN SCATTERING

    • Andre Childs Jr. ;
    • Ekaterina Vinogradova ;

    THU-900

    BIMETALLIC NANOSTARS AND THEIR EFFECTS IN SURFACE-ENHANCED RAMAN SCATTERING

    Andre Childs Jr., Ekaterina Vinogradova.

    The University of Texas at San Antonio, San Antonio, TX.

    Surface-enhanced Raman spectroscopy (SERS) is a tool to explore the vibrational properties of molecules. There are many applications for SERS in the bioscience field. In this experiment, we used SERS to study the surface adsorption and detection of the dye rhodamine 6G (R6G), bovine serum albumin (BSA), and a chlamydia extract known as CPAF using star-shaped gold/silver nanostars (Au/AgNps). We chose this particular morphology because it has been experimentally observed that nanostars display stronger SERS activity than particles with different shapes. The nanoparticles were synthesized through a solution-based growth method mediated by silver seeds that are used as the nucleating agent for anisotropic growth of gold colloids. The characterization of the Au/AgNPs was done by scanning electron microscopy (SEM) and UV-visible spectroscopy. Finally, we will discuss the SERS spectra of the R6G with the addition of the Au/AgNPs and the potential applications of this SERS-based technique in the biomedical field.

    THU-908 CHARACTERIZATION OF LIGHT SCATTERING FROM A LIGO-INPUT TEST MASS

    • Adrian Avila-Alvarez ;
    • Daniel Vander-Hyde ;
    • Joshua Hacker ;
    • Erik Muniz ;
    • Joshua Smith ;

    THU-908

    CHARACTERIZATION OF LIGHT SCATTERING FROM A LIGO-INPUT TEST MASS

    Adrian Avila-Alvarez, Daniel Vander-Hyde, Joshua Hacker, Erik Muniz, Joshua Smith.

    California State University, Fullerton, Fullerton, CA.

    The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a major project aimed at detecting astrophysical gravitational waves using laser interferometry. During quality control, one of LIGO’s input test masses, named ITM06, was found to have an abnormal cloudy anti-reflection coating on its secondary surface. It was not known how important this defect would be for scattering at the near infrared wavelength of 1,064 nm used by the LIGO lasers. A concern was that this flaw may alter the test mass’s scattered-light character and thereby decrease LIGO’s sensitivity to gravitational waves by adding nonlinear noise in the instrument readouts or by diminishing the overall laser power. To determine if the defect was visible in the infrared and to quantify its scatter, we measured ITM06 using the Fullerton imaging scatterometer. This apparatus illuminates the secondary surface with a 1,064 nm laser and takes pictures of the scattering for one-degree increments of the viewing angle. These pictures were then processed through a custom MATLAB script in which the bidirectional reflectance distribution function (BRDF) was computed for each angle to quantify its scatter. In these data, it was obvious that the infrared light lit up the cloudy defect. Despite this, the BRDF values were an acceptably low 4 x 10-7 str-1 (above 10 degrees). Our measurements confirmed that the abnormal coating does increase light scattering at 1,064-nm wavelengths, but the total scattering of ITM06 is still low enough for use in LIGO.