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Full-Text Articles in Physics

Spectroscopic Study On Pseudomonas Aeruginosa Biofilm In The Presence Of The Aptamer-Dna Scaffolded Silver Nanoclusters, Bidisha Sengupta, Prakash Adhikari, Esther Mallet, Ronald Havner, Prabhakar Pradhan Jan 2020

Spectroscopic Study On Pseudomonas Aeruginosa Biofilm In The Presence Of The Aptamer-Dna Scaffolded Silver Nanoclusters, Bidisha Sengupta, Prakash Adhikari, Esther Mallet, Ronald Havner, Prabhakar Pradhan

Faculty Publications

We report the effectiveness of silver nanocluster (Ag-NC) against the biofilm of Pseudomonas aeruginosa (PA). Two DNA aptamers specific for PA and part of their sequences were chosen as templates for growing the Ag-NC. While circular dichroism (CD) studies determined the presence of secondary structures, UV/Vis absorption, and fluorescence spectroscopic studies confirmed the formation of the fluorescent Ag-NC on the DNA templates. Furthermore, mesoscopic physics-based partial wave spectroscopy (PWS) was used to analyze the backscattered light signal that can detect the degree of nanoscale mass density/refractive index fluctuations to identify the biofilm formation, comparatively among the different aptamers with respect …


Analysis Of Beam Deflection Measurements In The Presence Of Linear Absorption, Manuel R. Ferdinandus, Jennifer Reed, Kent L. Averett, F. Kenneth Hopkins, Augustine Urbas May 2017

Analysis Of Beam Deflection Measurements In The Presence Of Linear Absorption, Manuel R. Ferdinandus, Jennifer Reed, Kent L. Averett, F. Kenneth Hopkins, Augustine Urbas

Faculty Publications

We develop a series of analytical approximations allowing for rapid extraction of the nonlinear parameters from beam deflection measurements. We then apply these approximations to the analysis of cadmium silicon phosphide and compare the results against previously published parameter extraction methods and find good agreement for typical experimental conditions.


Reflective Inverse Diffusion, Kenneth W. Burgi, Jessica Ullom, Michael A. Marciniak, Mark E. Oxley Nov 2016

Reflective Inverse Diffusion, Kenneth W. Burgi, Jessica Ullom, Michael A. Marciniak, Mark E. Oxley

Faculty Publications

Phase front modulation was previously used to refocus light after transmission through scattering media. This process has been adapted here to work in reflection. A liquid crystal spatial light modulator is used to conjugate the phase scattering properties of diffuse reflectors to produce a converging phase front just after reflection. The resultant focused spot had intensity enhancement values between 13 and 122 depending on the type of reflector. The intensity enhancement of more specular materials was greater in the specular region, while diffuse reflector materials achieved a greater enhancement in non-specular regions, facilitating non-mechanical steering of the focused spot. Scalar …


Controlling The Transmitted Field Into A Cylindrical Cloak's Hidden Region, Jeffrey S. Mcguirk, Peter J. Collins Oct 2008

Controlling The Transmitted Field Into A Cylindrical Cloak's Hidden Region, Jeffrey S. Mcguirk, Peter J. Collins

Faculty Publications

Constitutive parameters for simplified cylindrical cloaks have been developed such that εzµθ and εzµr match those of the ideal cylindrical cloak. Although they are not perfect, simplified cylindrical cloaks have been shown to inherit many of the power-bending properties of the ideal cloak. However, energy is transmitted into simplified cloaks' hidden regions. Here, we develop a constraint equation that can be used to determine how closely field behavior within the simplified cylindrical cloak matches that of the ideal cloak. The deviation from this controlling equation can be reduced by controlling the cloak's parameter value, …


Stimulated Brillouin Scattering Continuous Wave Phase Conjugation In Step-Index Fiber Optics, Steven M. Massey, Justin B. Spring, Timothy H. Russell Jul 2008

Stimulated Brillouin Scattering Continuous Wave Phase Conjugation In Step-Index Fiber Optics, Steven M. Massey, Justin B. Spring, Timothy H. Russell

Faculty Publications

Continuous wave (CW) stimulated Brillouin scattering (SBS) phase conjugation in step-index optical fibers was studied experimentally and modeled as a function of fiber length. A phase conjugate fidelity over 80% was measured from SBS in a 40 m fiber using a pinhole technique. Fidelity decreases with fiber length, and a fiber with a numerical aperture (NA) of 0.06 was found to generate good phase conjugation fidelity over longer lengths than a fiber with 0.13 NA. Modeling and experiment support previous work showing the maximum interaction length which yields a high fidelity phase conjugate beam is inversely proportional to the fiber …


Use Of A Continuous Wave Raman Fiber Laser In Graded-Index Multimode Fiber For Srs Beam Combination, Nathan B. Terry, Kevin T. Engel, Thomas G. Alley, Timothy H. Russell Jan 2007

Use Of A Continuous Wave Raman Fiber Laser In Graded-Index Multimode Fiber For Srs Beam Combination, Nathan B. Terry, Kevin T. Engel, Thomas G. Alley, Timothy H. Russell

Faculty Publications

We report using a Raman fiber laser (RFL) based on a multimode graded-index fiber as a novel method for beam combination of two continuous wave pump beams. Due to stimulated Raman scattering, the RFL generates a Stokes beam which can be up to 300% brighter than the pump beams. Up to 5.8 W of Stokes power is generated with an optical conversion efficiency of 56%.