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Luoyang, China

Ding C.,University of Sichuan | Pan L.,Luoyang Normal College | Lu B.,University of Sichuan
Applied Physics B: Lasers and Optics | Year: 2010

By using the generalized Huygens-Fresnel diffraction integral, the analytical expressions for the cross-spectral density matrix, spectral degree of polarization, orientation angle and degree of ellipticity of polarization ellipse of apertured stochastic electromagnetic modified Bessel-Gauss beams (MBGBs) through a paraxial optical ABCD system are derived, and used to study the changes in the state of polarization of apertured stochastic electromagnetic MBGBs propagating in free space. The invariance of the on-axis state of polarization of unapertured stochastic electromagnetic MBGBs propagating through paraxial optical ABCD systems is illustrated analytically and numerically. For apertured stochastic electromagnetic MBGBs, the on-axis spectral degree of polarization, orientation angle and degree of ellipticity of polarization ellipse increase with increasing propagation distance, and approach asymptotic values when the propagation distance is large enough. There is a uniform distribution region of the state of polarization around the center of the beams whose range decreases with increasing truncation parameter. In addition, the state of polarization of apertured stochastic electromagnetic MBGBs upon propagation can be modulated by controlling the truncation parameter. © 2009 Springer-Verlag. Source


Wang P.,Capital Normal University | Liu Z.,Luoyang Normal College
Journal of Raman Spectroscopy | Year: 2013

We report surface enhanced Raman spectroscopy (SERS) of Darling-Dennison resonance of thiourea on Ag electrode excited at 514.5 nm laser excitation. Darling-Dennison resonance indicates that two degenerate Raman modes interact with each other and their degenerate first-order overtone modes obtain energy and appear in Raman spectra. Our study showed that the ratio of intensity of the Darling-Dennison resonance is up to 0.24 of its fundamental Raman intensity, when the applied electrode voltage is at -0.4 V versus the saturated calomel electrode. This phenomenon was also observed on the Ag island film surface at ambient condition. These observations demonstrated strong evidence for Darling-Dennison resonance band in SERS. The implications of these observations are also discussed. Copyright © 2013 John Wiley & Sons, Ltd. Darling-Dennison resonance indicates that two degenerate Raman modes interact with each other and their degenerate first-order overtone modes obtain energy and appear in Raman spectra. The surface-enhanced Raman spectroscopy (SERS) of thiourea on Ag electrode excited at 514.5 nm laser excitation was obtained, and the combinational modes, which attributed to Darling-Dennison resonance, were observed in SERS on electrode and on silver island film, respectively, because of strong anharmonicity. Copyright © 2013 John Wiley & Sons, Ltd. Source


Tan Y.-G.,Luoyang Normal College | Cai Q.-Y.,CAS Wuhan Institute of Physics and Mathematics
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2016

Recently, Lucamarini et al. proposed the device-independent entanglement-based Bennett 1992 protocol [Phys. Rev. A 86, 032325 (2012)PLRAAN1050-294710.1103/PhysRevA.86.032325]. By exploiting the results in device-independent quantum key distribution with the Clauser-Horne-Shimony-Holt inequality, they claimed the security of their protocol. We will show, however, the way of encoding and the process for the latent eavesdropper to obtain the illegal information are different in these two protocols. Thus the security of their protocol cannot rely on Bell's theorem only. © 2016 American Physical Society. Source


Li J.,Taiyuan University of Science and Technology | Ding C.,Luoyang Normal College | Lu B.,University of Sichuan
Applied Physics B: Lasers and Optics | Year: 2011

By using the extended Huygens-Fresnel principle, the analytical expressions for the generalized Stokes parameters of random electromagnetic Gaussian Schell-model (GSM) vortex beams propagating through atmospheric turbulence are derived, and used to study the changes in spectral Stokes parameters of random electromagnetic GSM vortex beams in atmospheric turbulence and to compare the results of random electromagnetic GSM vortex-free beams. The influence of atmospheric turbulence on the spectral Stokes parameters is analyzed. The validity of our results is interpreted physically. © Springer-Verlag 2010. Source


Shi Y.P.,Luoyang Normal College
WIT Transactions on Information and Communication Technologies | Year: 2014

A kind of MELP vocoder based on FPGA is designed in this paper. Firstly, it expatiate the MELP algorithm, then the idea of modeling and realization process on FPGA by using DSP Builder in Matlab based is proposed. At last we can complete the function simulation of the encoding and decoding system, and the simulation result shows that the synthetical signals fit well with the original ones, and the quality of the speech got from the vocoder is good. © 2014 WIT Press. Source

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