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Thermomechanical Oscillations In Hybrid Nematic Liquid Crystals, R. S. Hakobyan, G. L. Yesayan, B. Ya. Zeldovich
Thermomechanical Oscillations In Hybrid Nematic Liquid Crystals, R. S. Hakobyan, G. L. Yesayan, B. Ya. Zeldovich
Faculty Bibliography 2000s
Thermomechanical oscillations observed previously in hybrid oriented nematic liquid crystals (NLCs) are explained theoretically. The effect is conditioned by the hydrodynamic flow tendency to reduce the curvature of the "flexible ribbon" of hybrid NLCs. There is qualitative agreement between the theoretical calculations and the experimental results.
Analysis And Optimization Of A Maglev System Based On The Halbach Magnet Arrays, C. Ham, W. Ko, Q. Han
Analysis And Optimization Of A Maglev System Based On The Halbach Magnet Arrays, C. Ham, W. Ko, Q. Han
Faculty Bibliography 2000s
A systematic analysis and an optimization are presented for an electrodynamic suspension Maglev system based on the Halbach magnet arrays that promises to develop a feasible Maglev system. The magnetic field was modeled using scalar potential and Fourier series methods and then confirmed with the corresponding finite element method (FEM) result. The optimization of the array was derived based on the performance index defined as the ratio of the square of flux to the magnet weight of a unit volume. The study results were applied to the Maglev system at the University of Central Florida for measuring the current capability …
Spatially Tunable Laser Emission In Dye-Doped Photonic Liquid Crystals, Yuhua Huang, Ying Zhou, Shin-Tson Wu
Spatially Tunable Laser Emission In Dye-Doped Photonic Liquid Crystals, Yuhua Huang, Ying Zhou, Shin-Tson Wu
Faculty Bibliography 2000s
A spatially tunable laser emission of the dye-doped cholesteric liquid crystal (CLC) cell using a one-dimensional temperature gradient is demonstrated. The photoexcitation of dye-doped CLC device using a frequency-doubled pulsed Nd: yttrium-aluminium-garnet laser gives rise to laser emission in the yellow-red spectral range. The lasing wavelength is widely tunable from 577 to 670 nm by shifting the position of the dye-doped CLC cell with respect to the pumping beam. The lowest excitation energy and maximum lasing efficiency occur at lambda similar to 605 nm which corresponds to the peak fluorescence emission of the dye.
Adaptive Lens Using Liquid Crystal Concentration Redistribution, Hongwen Ren, Yi-Hsin Lin, Shin-Tson Wu
Adaptive Lens Using Liquid Crystal Concentration Redistribution, Hongwen Ren, Yi-Hsin Lin, Shin-Tson Wu
Faculty Bibliography 2000s
An adaptive lens using electrically induced liquid crystal (LC)/monomer concentration redistribution is demonstrated. In the absence of an electric field, the LC/monomer mixture is homogeneously distributed. Application of an inhomogeneous electric field causes the LC molecules to diffuse towards the high field region and the liquid monomer towards the low field region. On the other hand, the LC molecules tend to diffuse from high to low concentration direction in order to balance the concentration change. A gradient LC concentration is thus obtained. Using the gradient LC concentration, we demonstrate a tunable-focus lens. Compared with a conventional LC lens, our lens …
Confined Propagation And Near Single-Mode Laser Oscillation In A Gain-Guided, Index Antiguided Optical Fiber, A. E. Siegman, Ying Chen, Vikas Sudesh, Martin C. Richardson, Michael Bass, Paul Foy, Wade Hawkins, John Ballato
Confined Propagation And Near Single-Mode Laser Oscillation In A Gain-Guided, Index Antiguided Optical Fiber, A. E. Siegman, Ying Chen, Vikas Sudesh, Martin C. Richardson, Michael Bass, Paul Foy, Wade Hawkins, John Ballato
Faculty Bibliography 2000s
The authors report laser oscillation in what appears to be a single transverse mode with very large mode area in optical fibers having heavily Nd-doped 100 mu m diameter cores with refractive index significantly lower in the core than in the surrounding cladding. Since fibers of this type cannot support conventional index-guided modes, their results appear to confirm a recent analysis which predicts gain-guided single-mode propagation in index antiguided fibers, provided the gain coefficient in the core exceeds a threshold value. Fibers of this type may be of significant interest for amplifiers and oscillators having large power outputs and/or small …