The Experts below are selected from a list of 10893 Experts worldwide ranked by ideXlab platform
Ning Wang - One of the best experts on this subject based on the ideXlab platform.
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Stokes Parameter analysis of a packet of turbulence generating gravity waves
Journal of Geophysical Research, 2005Co-Authors: Steven E. Koch, Ning WangAbstract:[1] Stokes Parameter analysis for small-scale gravity waves was carried out from a set of aircraft observational data. The goal is to understand the polarization properties associated with gravity waves when turbulence is generated so that enough physical knowledge can be gained about the interaction between the two. A wavelet cross-spectrum technique is introduced into the traditional Stokes Parameter analysis. From this analysis it is shown that small-scale gravity waves possess distinctive polarization signatures. Further extension of the Stokes Parameter analysis by a wave-averaging method is also proposed. The analysis using this method indicates that the turbulence production is closely related to an enhanced level of polarization and coherency in the two components of the horizontal wind in the gravity waves and that the turbulence surge is accompanied by a tendency for an instantaneous reduction of polarization and abrupt shift of horizontal wave vector of the progenitor gravity waves. These findings may be useful in the prediction of the occurrence of turbulence in association with gravity wave activities in the atmosphere.
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Stokes Parameter analysis of a packet of turbulence‐generating gravity waves
Journal of Geophysical Research, 2005Co-Authors: Steven E. Koch, Ning WangAbstract:[1] Stokes Parameter analysis for small-scale gravity waves was carried out from a set of aircraft observational data. The goal is to understand the polarization properties associated with gravity waves when turbulence is generated so that enough physical knowledge can be gained about the interaction between the two. A wavelet cross-spectrum technique is introduced into the traditional Stokes Parameter analysis. From this analysis it is shown that small-scale gravity waves possess distinctive polarization signatures. Further extension of the Stokes Parameter analysis by a wave-averaging method is also proposed. The analysis using this method indicates that the turbulence production is closely related to an enhanced level of polarization and coherency in the two components of the horizontal wind in the gravity waves and that the turbulence surge is accompanied by a tendency for an instantaneous reduction of polarization and abrupt shift of horizontal wave vector of the progenitor gravity waves. These findings may be useful in the prediction of the occurrence of turbulence in association with gravity wave activities in the atmosphere.
Susumu Sato - One of the best experts on this subject based on the ideXlab platform.
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determination of anchoring energy in nematic liquid crystal cells with controllable twist angles using a Stokes Parameter method
Japanese Journal of Applied Physics, 2004Co-Authors: Marenori Kawamura, Yoshiaki Goto, Susumu SatoAbstract:An accurate measurement method for determining the two-dimensional distribution of an azimuthal anchoring energy is developed by continuously controlling the combination angle between two rubbing alignment films of a sample liquid crystal cell. The anchoring energy can be precisely obtained by measuring actual cell Parameters, such as cell thickness and the twist angle of the liquid crystal (LC) cell by torque balance and Stokes Parameter methods.
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two dimensional measurements of cell Parameter distributions in reflective liquid crystal displays by using multiple wavelengths Stokes Parameters
Journal of Applied Physics, 2004Co-Authors: Marenori Kawamura, Yoshiaki Goto, Susumu SatoAbstract:We propose a two-dimensional measurement method of cell Parameters such as a cell thickness, twist angle, and pretilt angle in reflective liquid crystal (LC) cells by using Stokes Parameters of reflected light at several wavelengths. The cell thickness of the reflective LC cells can be measured by calculating the Stokes Parameter equations at only one wavelength, and both the cell thickness and twist angle can also be determined at two wavelengths, where the twist angle and/or pretilt angle of designed values are used. Three cell Parameters including the pretilt angle as well as the cell thickness and twist angle can also be measured by using three wavelengths Stokes Parameter equations. Two-dimensional LC cell Parameters are easily obtained and their mapping results are successfully demonstrated.
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Pretilt angle measurement of reflective liquid crystal cells by plural-wavelength Stokes Parameter method
Liquid Crystals VII, 2003Co-Authors: Marenori Kawamura, Yoshiaki Goto, Susumu SatoAbstract:Stokes Parameter methods to determine cell Parameters such as a pretilt angle, thickness and twist angle in reflective liquid crystal (LC) cells have been developed by measuring Stokes Parameters of reflected light at plural wavelengths. The cell thickness can be determined by measuring one-wavelength Stokes Parameters including a near-infrared wavelength, and both the cell thickness and twist angle can also be determined by calculating the Stokes Parameter at two wavelengths. Furthermore, these cell Parameters containing the pretilt angle as well as cell the cell thickness and twist angle can be determined by using Stokes Parameters at three wavelengths. These methods can be applied to determine two-dimensional (2D) cell Parameter distributions of the reflective LC cell by using a high resolution CCD camera.
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near infrared Stokes Parameter method for determining two dimensional cell thickness and twist angle distributions of liquid crystal color displays
Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, 2002Co-Authors: Marenori Kawamura, Susumu SatoAbstract:We propose a two-dimensional (2D) and hyperfine measurement method for precisely determining cell Parameter distributions such as a cell thickness and twist angle in color liquid crystal (LC) displays. The 2D cell thickness and twist angle distributions can easily be determined by measuring Stokes Parameters of all pixels for red, green and blue in LCD panel at a wavelength of near-infrared region, because the transmission light at the wavelength is not absorbed by each color filter. In addition, the spatial resolution can be improved by increasing the magnification of the objective lens in front of a high resolution CCD camera. These cell Parameters of each pixel in the practical LCD panel are compared and discussed.
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evaluation of cell Parameters of tn liquid crystal cells by using a Stokes Parameter method
Molecular Crystals and Liquid Crystals, 2001Co-Authors: Masaki Okabe, Makoto Kaneko, Toshiaki Maehara, Yoshihiro Togashi, Susumu SatoAbstract:Abstract Evaluation of cell thickness and a twist angle of a liquid crystal layer is very important in the liquid crystal study and manufacturing. We have developed an analysis system of the cell thickness and the twist angle of the liquid crystal layer, named ‘LCD Analyzer’, which is based on the Stokes Parameter Method. We have examined the effects of the performance of the optics on the measurement and a measuring condition, and achieved good precision of evaluating the cell Parameters.
Steven E. Koch - One of the best experts on this subject based on the ideXlab platform.
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Stokes Parameter analysis of a packet of turbulence generating gravity waves
Journal of Geophysical Research, 2005Co-Authors: Steven E. Koch, Ning WangAbstract:[1] Stokes Parameter analysis for small-scale gravity waves was carried out from a set of aircraft observational data. The goal is to understand the polarization properties associated with gravity waves when turbulence is generated so that enough physical knowledge can be gained about the interaction between the two. A wavelet cross-spectrum technique is introduced into the traditional Stokes Parameter analysis. From this analysis it is shown that small-scale gravity waves possess distinctive polarization signatures. Further extension of the Stokes Parameter analysis by a wave-averaging method is also proposed. The analysis using this method indicates that the turbulence production is closely related to an enhanced level of polarization and coherency in the two components of the horizontal wind in the gravity waves and that the turbulence surge is accompanied by a tendency for an instantaneous reduction of polarization and abrupt shift of horizontal wave vector of the progenitor gravity waves. These findings may be useful in the prediction of the occurrence of turbulence in association with gravity wave activities in the atmosphere.
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Stokes Parameter analysis of a packet of turbulence‐generating gravity waves
Journal of Geophysical Research, 2005Co-Authors: Steven E. Koch, Ning WangAbstract:[1] Stokes Parameter analysis for small-scale gravity waves was carried out from a set of aircraft observational data. The goal is to understand the polarization properties associated with gravity waves when turbulence is generated so that enough physical knowledge can be gained about the interaction between the two. A wavelet cross-spectrum technique is introduced into the traditional Stokes Parameter analysis. From this analysis it is shown that small-scale gravity waves possess distinctive polarization signatures. Further extension of the Stokes Parameter analysis by a wave-averaging method is also proposed. The analysis using this method indicates that the turbulence production is closely related to an enhanced level of polarization and coherency in the two components of the horizontal wind in the gravity waves and that the turbulence surge is accompanied by a tendency for an instantaneous reduction of polarization and abrupt shift of horizontal wave vector of the progenitor gravity waves. These findings may be useful in the prediction of the occurrence of turbulence in association with gravity wave activities in the atmosphere.
Ari T. Friberg - One of the best experts on this subject based on the ideXlab platform.
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Temporal electromagnetic degree of coherence and Stokes-Parameter modulations in Michelson’s interferometer
Applied Physics B, 2016Co-Authors: Lasse-petteri Leppänen, Ari T. Friberg, Tero SetäläAbstract:We show that for a stationary, quasi-monochromatic, partially polarized beam the temporal electromagnetic degree of coherence is specified by the modulation contrasts of the Stokes Parameters in Michelson’s interferometer. We also demonstrate how the polarization modulations are transferred into intensity variations, thereby enabling the measurement of the time-domain degree of coherence and the associated coherence time. Our results are analogous to those found earlier for spatial electromagnetic coherence in Young’s interferometer and form an extension to the customary scalar treatment of Michelson’s interferometer. Our work also highlights the relationship between polarization and electromagnetic coherence and the time-domain analyses of these quantities in terms of the traditional (polarization) Stokes Parameters and the recently introduced coherence (two-time) Stokes Parameters.
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temporal electromagnetic degree of coherence and Stokes Parameter modulations in michelson s interferometer
Applied Physics B, 2016Co-Authors: Lasse-petteri Leppänen, Ari T. Friberg, Tero SetäläAbstract:We show that for a stationary, quasi-monochromatic, partially polarized beam the temporal electromagnetic degree of coherence is specified by the modulation contrasts of the Stokes Parameters in Michelson’s interferometer. We also demonstrate how the polarization modulations are transferred into intensity variations, thereby enabling the measurement of the time-domain degree of coherence and the associated coherence time. Our results are analogous to those found earlier for spatial electromagnetic coherence in Young’s interferometer and form an extension to the customary scalar treatment of Michelson’s interferometer. Our work also highlights the relationship between polarization and electromagnetic coherence and the time-domain analyses of these quantities in terms of the traditional (polarization) Stokes Parameters and the recently introduced coherence (two-time) Stokes Parameters.
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contrasts of Stokes Parameters in young s interference experiment and electromagnetic degree of coherence
Optics Letters, 2006Co-Authors: Tero Setälä, Jani Tervo, Ari T. FribergAbstract:We analyze the modulation of the Stokes Parameters in Young's two-pinhole interference experiment with a random electromagnetic beam. We demonstrate that the electromagnetic (spectral) degree of coherence put forward in Opt. Lett.29, 328 (2004) [or its space-time analog in Opt. Express11, 1137 (2003)] is physically related to the contrasts of modulation in the four Stokes Parameters. More explicitly, the electromagnetic degree of coherence is a measure of both the visibility of the intensity fringes and the modulation contrasts of the three polarization Stokes Parameters. We also show that by using suitable wave plates the modulation in any Stokes Parameter can be transformed into the form of intensity variation, and hence the electromagnetic degree of coherence can be obtained experimentally by four visibility measurements.
Tero Setälä - One of the best experts on this subject based on the ideXlab platform.
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Temporal electromagnetic degree of coherence and Stokes-Parameter modulations in Michelson’s interferometer
Applied Physics B, 2016Co-Authors: Lasse-petteri Leppänen, Ari T. Friberg, Tero SetäläAbstract:We show that for a stationary, quasi-monochromatic, partially polarized beam the temporal electromagnetic degree of coherence is specified by the modulation contrasts of the Stokes Parameters in Michelson’s interferometer. We also demonstrate how the polarization modulations are transferred into intensity variations, thereby enabling the measurement of the time-domain degree of coherence and the associated coherence time. Our results are analogous to those found earlier for spatial electromagnetic coherence in Young’s interferometer and form an extension to the customary scalar treatment of Michelson’s interferometer. Our work also highlights the relationship between polarization and electromagnetic coherence and the time-domain analyses of these quantities in terms of the traditional (polarization) Stokes Parameters and the recently introduced coherence (two-time) Stokes Parameters.
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temporal electromagnetic degree of coherence and Stokes Parameter modulations in michelson s interferometer
Applied Physics B, 2016Co-Authors: Lasse-petteri Leppänen, Ari T. Friberg, Tero SetäläAbstract:We show that for a stationary, quasi-monochromatic, partially polarized beam the temporal electromagnetic degree of coherence is specified by the modulation contrasts of the Stokes Parameters in Michelson’s interferometer. We also demonstrate how the polarization modulations are transferred into intensity variations, thereby enabling the measurement of the time-domain degree of coherence and the associated coherence time. Our results are analogous to those found earlier for spatial electromagnetic coherence in Young’s interferometer and form an extension to the customary scalar treatment of Michelson’s interferometer. Our work also highlights the relationship between polarization and electromagnetic coherence and the time-domain analyses of these quantities in terms of the traditional (polarization) Stokes Parameters and the recently introduced coherence (two-time) Stokes Parameters.
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contrasts of Stokes Parameters in young s interference experiment and electromagnetic degree of coherence
Optics Letters, 2006Co-Authors: Tero Setälä, Jani Tervo, Ari T. FribergAbstract:We analyze the modulation of the Stokes Parameters in Young's two-pinhole interference experiment with a random electromagnetic beam. We demonstrate that the electromagnetic (spectral) degree of coherence put forward in Opt. Lett.29, 328 (2004) [or its space-time analog in Opt. Express11, 1137 (2003)] is physically related to the contrasts of modulation in the four Stokes Parameters. More explicitly, the electromagnetic degree of coherence is a measure of both the visibility of the intensity fringes and the modulation contrasts of the three polarization Stokes Parameters. We also show that by using suitable wave plates the modulation in any Stokes Parameter can be transformed into the form of intensity variation, and hence the electromagnetic degree of coherence can be obtained experimentally by four visibility measurements.