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Full-Text Articles in Physics

Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal Apr 2015

Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal

Krishna C. Mandal

No abstract provided.


Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal Apr 2015

Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal

Krishna C. Mandal

No abstract provided.


Basic Astronomy Labs, Terry L. Smith, Michael D. Reynolds, Jay S. Huebner Jul 2014

Basic Astronomy Labs, Terry L. Smith, Michael D. Reynolds, Jay S. Huebner

Jay S Huebner

Providing the tools and know-how to apply the principles of astronomy first-hand, these 43 laboratory exercises each contain an introduction that clearly shows budding astronomers why the particular topic of that lab is of interest and relevant to astronomy. About one-third of the exercises are devoted solely to observation, and no mathematics is required beyond simple high school algebra and trigonometry.Organizes exercises into six major topics—sky, optics and spectroscopy, celestial mechanics, solar system, stellar properties, and exploration and other topics—providing clear outlines of what is involved in the exercise, its purpose, and what procedures and apparatus are ...


Four-Domain Twisted Nematic Liquid Crystal Display Fabricated By Reverse Rubbed Polyimide Process, J. Chen, Philip J. Bos, D. L. Johnson, Douglas R. Bryant, J. Li, S. H. Jamal, J. R. Kelly Oct 2013

Four-Domain Twisted Nematic Liquid Crystal Display Fabricated By Reverse Rubbed Polyimide Process, J. Chen, Philip J. Bos, D. L. Johnson, Douglas R. Bryant, J. Li, S. H. Jamal, J. R. Kelly

Philip J. Bos

In Appl. Phys. Lett. 67, 1990 (1995), we proposed a particularly simple four‐domain (4‐D) twisted nematic(TN) liquid crystal display(LCD) device, which is composed of two left‐handed and two right‐handed TN subpixels. The two members of each pair of same handedness subpixels are rotated 180° with respect to each other, resulting in four domains that spatially average one another optically to provide a wide angle of viewing with no gray scale inversion. The optical performance of the 4‐D TN LCD was confirmed by studies of a test cell fabricated by a two‐step SiO ...


Modeling And Performance Limits Of A Large Aperture High-Resolution Wavefront Control System Based On A Liquid Crystal Spatial Light Modulator, Xinghua Wang, Bin Wang, Philip J. Bos Oct 2013

Modeling And Performance Limits Of A Large Aperture High-Resolution Wavefront Control System Based On A Liquid Crystal Spatial Light Modulator, Xinghua Wang, Bin Wang, Philip J. Bos

Philip J. Bos

The aberration introduced by the primary optical element of a lightweight large aperture telescope can be corrected with a diffractive optical element called the liquid crystal spatial light modulator. Such aberration is usually very large, which makes the design and modeling of such a system difficult. A method to analyze the system is introduced, and the performance limitation of the system is studied through extensive modeling. An experimental system is demonstrated to validate the analysis. The connection between the modeling data and the experimental data is given.


Optical Switching With Cold Atoms, Andrew Dawes May 2013

Optical Switching With Cold Atoms, Andrew Dawes

Andrew M C Dawes

A Viewpoint on: Efficient All-Optical Switching Using Slow Light within a Hollow Fiber M. Bajcsy, S. Hofferberth, V. Balic, T. Peyronel, M. Hafezi, A. S. Zibrov, V. Vuletic, and M. D. Lukin Phys. Rev. Lett. 102, 203902 (2009) – Published May 18, 2009


Short-Range Tests Of Gravitational Physics, Holly Leopardi, David Alan Smith Apr 2013

Short-Range Tests Of Gravitational Physics, Holly Leopardi, David Alan Smith

David Smith

Due to the incompatibility of the Standard Model and General Relativity, tests of gravity remain at the forefront of experimental physics research. At Humboldt State University, undergraduates and faculty are developing an experiment that will test gravitational interactions below the 50-micron distance scale. The experiment will measure the twist of a torsion pendulum as an attractor mass is oscillated nearby in a parallel-plate configuration, providing a time varying torque on the pendulum. The size and distance dependence of the torque variation will provide means to determine deviations from accepted models of gravity on untested distance scales. To observe the twist ...


Tests Of Gravity Below The 50-Micron Distance Scale, David Alan Smith, C.D. Hoyle, Holly Leopardi Nov 2012

Tests Of Gravity Below The 50-Micron Distance Scale, David Alan Smith, C.D. Hoyle, Holly Leopardi

David Smith

Though it is the oldest recognized of the fundamental forces, tests of gravity remain at the forefront of experimental physics research. Due to the incompatibility of the Standard Model and General Relativity, there is no accepted Unified Field Theory, though some attempts to construct such a model via String Theory predict more than three spatial dimensions that could alter the gravitational Inverse-Square Law at short distances. Certain scenarios also predict unobserved subatomic particles that may cause short-range violations of the Weak Equivalence Principle. The Gravitational Research Laboratory at Humboldt State University, a collaboration of undergraduate students and faculty, is developing ...


Microwave Optics Research, Allen Andersen, Todd Lines, Josh Barney Mar 2012

Microwave Optics Research, Allen Andersen, Todd Lines, Josh Barney

Allen Andersen

The BYU-Idaho Physics Department x-band microwave optics equipment was originally intended for use in classroom demonstrations. I evaluated this equipment for use in research. I designed and built additional equipment needed in order to perform attenuation and other experiments then used it to conduct research on the transmission properties of paper and other substances. The new equipment allowed me to create a standard experimental procedure, take reasonably accurate measurements, and reduce undesired standing wave effects. Mathematical and experimental analysis was done to determine the necessary parameters of the new equipment. The new apparatus is comparable to setups featured in published ...


Why Magnification Works, Terry L. Smith, Jay S. Huebner Jan 1994

Why Magnification Works, Terry L. Smith, Jay S. Huebner

Jay S Huebner

The simplest way to magnify the view of a small object is to bring the object closer to the eye, and of course science teachers know about magnifying glasses, telescopes, and microscopes.But why magnification works seems intuitive and is not usually explained to our students. We present here a few ideas on magnification that we use in our classroom and some general information on vision that we hope will be helpful to other teachers.


Viscoelastic Properties Of A Liquid-Crystalline Monomer And Its Dimer, Gregory A. Dilisi, Charles Rosenblatt, Anselm C. Griffin, Uma Hari Mar 1992

Viscoelastic Properties Of A Liquid-Crystalline Monomer And Its Dimer, Gregory A. Dilisi, Charles Rosenblatt, Anselm C. Griffin, Uma Hari

Gregory A. DiLisi

Quasielastic-light-scattering measurements are reported for a dialkoxyphenylbenzoate monomer and its dimer in their respective nematic phases. The splay and twist elastic moduli of the dimer are found to be nearly independent of molecular length. The dimer's bend modulus, however, shows an anomalous increase with decreasing temperature well below the nematic-isotropic phase transition. Monomer viscosities are consistent with typical literature values, although y, /g, pf y and gb,„d seem to be larger than expected for the dimer, where y& is the twist viscosity. The results are discussed in terms of viscoelastic properties of semiflexible rods. The elastic properties in ...


Optical Transformations In Three-Space: Simulations With A Pc, Raymond G. Wilson, Sean M. Mccreary, Jeffrey L. Thompson Dec 1991

Optical Transformations In Three-Space: Simulations With A Pc, Raymond G. Wilson, Sean M. Mccreary, Jeffrey L. Thompson

Raymond Wilson

Using Fourier transform and convolution techniques, it is illustrated how all aspects of Fraunhofer diffraction of virtually any aperture real or complex can be calculated and displayed in two- and three-space using an IBM-compatible PC. Details of program commands using software Matlab are illustrated as well as results of plotting software Surfer. Fresnel diffraction is illustrated using Fourier transformation.


Anomaly In The Dynamic Behavior Of The Electroclinic Effect Below The Nematic—Smectic-A Phase Transition, Gregory A. Dilisi, Zili Li, Robert B. Akins, Charles Rosenblatt, Rolfe G. Petscheck Dec 1990

Anomaly In The Dynamic Behavior Of The Electroclinic Effect Below The Nematic—Smectic-A Phase Transition, Gregory A. Dilisi, Zili Li, Robert B. Akins, Charles Rosenblatt, Rolfe G. Petscheck

Gregory A. DiLisi

The electroclinic effect and dielectric response have been investigated in the British Drug House material SCE12 over its entire 15-K smectic-A range. Near the smectic-A —srnectic-C -phase transition both the electroclinic coefficient and dynamic response behave normally, the former diverging and the latter exhibiting a critical slowing down on approaching T + from above. Similar behav- A-C ior is seen in the dielectric response. Approximately 10 to 12 K above T ~, however, it was found A-C that the electroclinic relaxation time levels off and even begins to increase again on approaching the nematic —smectic-A transition from below. The magnitude of the ...


Nematic Electroclinic Effect, Gregory A. Dilisi, Zili Li, Rolfe G. Pescheck, Charles Rosenblatt Dec 1989

Nematic Electroclinic Effect, Gregory A. Dilisi, Zili Li, Rolfe G. Pescheck, Charles Rosenblatt

Gregory A. DiLisi

A tilt 0 of the principal axis of the optical dielectric tensor linear in a transverse electric field was observed for a surface-stabilized nematic liquid crystal. The electroclinic coefficient dOldE was observed to increase rapidly on approaching the nematic —smectic-A phase transition from above. This was not expected, and indicates that the incipient translational order is important to the electroclinic effect. The data are consistent with a critical exponent only over a narrow range of temperature, and in this range the apparent exponent is not that expected from theory. In addition, dielectric data are presented for this transition, and birefringence ...