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Wyszukujesz frazę "Zhao, J. J." wg kryterium: Autor


Wyświetlanie 1-10 z 10
Tytuł:
Changes in the states of polarization of random electromagnetic beams in atmospheric turbulence
Autorzy:
Li, J.
Zhao, K.
Lai, Y.
Powiązania:
https://bibliotekanauki.pl/articles/174110.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
non-Kolmogorov atmospheric turbulence
random electromagnetic beams
degree of polarization
orientation angle
degree of ellipticity
Opis:
Taking the random electromagnetic cosh-Gaussian beam as a typical example of random electromagnetic beams, the analytical expressions for the cross-spectral density matrix element of random electromagnetic cosh-Gaussian beams propagating through non-Kolmogorov atmospheric turbulence are derived, and used to study the changes in the states of polarization (degree of polarization, orientation angle and degree of ellipticity) of random electromagnetic cosh-Gaussian beams in non-Kolmogorov atmospheric turbulence. It is shown that the states of polarization of random electromagnetic cosh-Gaussian beams in non-Kolmogorov atmospheric turbulence are different from those in free space. The degree of polarization decreases, and the orientation angle and degree of ellipticity increase with increasing structure constant. The on-axis degree of polarization and the degree of ellipticity appear to have an oscillatory behavior and the orientation angle has a rapid transition for the larger cosh-part parameter of random electromagnetic cosh-Gaussian beams in atmospheric turbulence.
Źródło:
Optica Applicata; 2017, 47, 1; 51-62
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical generation of ultra-wideband signals with a reconfigurable spectral notch-band
Autorzy:
Xiang, P.
Chen, Y.
Chen, D.
Zhao, J.
Powiązania:
https://bibliotekanauki.pl/articles/174353.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
ultra-wideband (UWB)
ultra-wideband over fiber
notch-band
interference avoidance
Opis:
A novel method for optical generation of ultra-wideband signals with a reconfigurable spectral notch-band is proposed. In the proposed system, ultra-wideband signals are generated in the optical domain and an optical tunable delay line is deployed to introduce a notch-band to the spectral profile of the generated ultra-wideband signals, which can effectively avoid the signal interference between ultra-wideband signals and pre-planned narrowband wireless signals used in wireless local area networks (WLAN). A theoretical model describing the proposed system is derived; the optical generation and fiber transmission of ultra-wideband signals with a reconfigurable notch-band are demonstrated via computer simulations.
Źródło:
Optica Applicata; 2014, 44, 3; 411-419
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectral degrees of cross-polarization of stochastic anisotropic electromagnetic beams in modified non-Kolmogorov atmospheric turbulence
Autorzy:
Chen, F.
Chen, J.
Zhao, Q.
Chen, Y
Xin, Y.
Li, J.
Pan, H.
Powiązania:
https://bibliotekanauki.pl/articles/174614.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
quasi-homogenous source
modified non-Kolmogorov turbulence
generalized Stokes parameters
Opis:
Based on the extended Huygens–Fresnel principle, variations in generalized Stokes parameters of stochastic anisotropic electromagnetic beams propagating through modified non-Kolmogorov atmospheric turbulence have been analyzed. The changes in generalized Stokes parameters with different turbulence parameters and source parameters were analyzed first. After that, the distributions of the spectral degrees of cross-polarization (SDCP) of isotropic beams and anisotropic beams were simulated. The results show that the profiles of distribution of SDCP of these two kinds of beams are very different in the near field, and will fluctuate through the propagation in atmospheric turbulence, but at last, when the propagation distance is long enough, the difference in the source makes a slight difference in the final profiles of SDCP in the output plane. They mainly depended on the turbulence perturbation, and in the weak turbulence, the profiles of final distribution show more flatter features.
Źródło:
Optica Applicata; 2013, 43, 4; 773-783
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improvement of accuracy of simple methods for design and analysis of a blazed phase grating microstructure
Autorzy:
Wang, W.
Jing, X.
Zhao, J.
Li, Y.
Tian, Y.
Powiązania:
https://bibliotekanauki.pl/articles/173533.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
grating
effective medium theory
scalar diffraction theory
Opis:
In order to precisely analyze and design the transmittance characteristics of a blazed grating, the validity of both the scalar diffraction theory and the effective medium theory is quantitatively demonstrated. By making a comparison of diffraction efficiencies calculated by the two simplified methods and Fourier modal method, the accuracy can be obtained. It is found that when the normalized period is more than three wavelengths of the incident light, the scalar diffraction theory is useful to calculate the transmittance of the blazed grating within the error of less than 3%. The validity of the scalar diffraction theory increases when the normalized period increases. Importantly, by considering the Fresnel reflection effect, the validity of scalar diffraction theory can be significantly enhanced. Furthermore, when no higher-order diffraction waves appear and only zeroth order diffraction wave propagates, the effective medium theory is accurate to compute the diffraction efficiency within the difference of less than 1% between the zeroth order effective medium theory and Fourier modal method. The polarization characteristics of the validity of effective medium theory are also quantitatively demonstrated. The validity of the two simplified theories is dependent on not only the normalized period of surface microstructure but also the normalized groove depth.
Źródło:
Optica Applicata; 2017, 47, 2; 183-198
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generalized Stokes parameters of random electromagnetic quasi-homogeneous beams on propagation
Autorzy:
Chen, J
Xin, Y
Chen, Y
Chen, F
Zhao, Q
Powiązania:
https://bibliotekanauki.pl/articles/174819.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
electromagnetic
quasi-homogeneous
generalized Stokes parameters
polarization
Opis:
The expressions for the elements of the on-axis and transverse generalized Stokes parameters of random electromagnetic quasi-homogeneous beams on propagation are presented and are used to study the polarization properties of the beams. Some typical numerical calculations of the on-axis and transverse Stokes parameters, polarization properties of the beams on propagation are illustrated. The results show that for different sources all the on-axis parameters are identical in the near field and keep fixed values in the far field. But the transverse parameters are affected greatly by the properties of the source even in the near field. We have also found that the spatial profiles of the transverse parameters remain unchanged upon propagation.
Źródło:
Optica Applicata; 2013, 43, 2; s. 205-216
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polarization dependence of patterning effects in quantum well semiconductor optical amplifier-based wavelength conversion
Autorzy:
Qin, C
Shen, W
Zhao, J.
Yu, H.
Xu, E
Powiązania:
https://bibliotekanauki.pl/articles/173469.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
semiconductor optical amplifiers
polarization
patterning effect
Opis:
In this paper, polarization dependence of patterning effects in quantum well semiconductor optical amplifier-based wavelength conversion is experimentally and theoretically investigated. The carrier and photon density rate equations are numerically solved by using the time-domain traveling wave model. The material gain calculation, including the strain effect in the active layer, is based on the k·p method. By comparing experimental and computational results, it is demonstrated that the polarization of the injection signal has a significant influence on the gain recovery time of quantum well semiconductor optical amplifier. Under the cross-polarized signals injection, the output signals suffer the weakest and strongest patterning effects both for unstrained and tensile strained quantum well semiconductor optical amplifiers.
Źródło:
Optica Applicata; 2015, 45, 2; 163-172
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Defect solitons supported by kagome photonic lattices in biased photovoltaic-photorefractive crystals
Autorzy:
Hui, J.
Lu, K.
Zhao, C.
Gao, L.
Chen, W.
Powiązania:
https://bibliotekanauki.pl/articles/173797.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
defect solitons
photonic lattices
photorefractive nonlinearity
nonlinear optics
Opis:
We report that defect solitons can be supported by kagome photonic lattices with a defect in biased photovoltaic-photorefractive crystals. For a positive defect, these defect solitons exist only in the semi-infinite bandgap and are stable in the low power region but unstable in the high power region. For a negative defect, these defect solitons exist in both of the semi-infinite bandgaps and the first bandgap. In the semi-infinite bandgap, low-power defect solitons are stable when the negative defect depth is low and unstable when the negative defect depth is high, moderate-power defect solitons are stable when the negative defect depth is high, and high-power defect solitons are unstable for all the negative defect depths. In the first bandgap, defect solitons are stable in all the power regions when the negative defect depth is low. When the negative defect depth is high, defect solitons are stable in the high power region and unstable in the low power region. On the other hand, these defect solitons are those studied previously in kagome photonic lattices with a defect in biased non-photovoltaic-photorefractive crystals when the bulk photovoltaic effect is negligible and those in kagome photonic lattices with a defect in photovoltaic-photorefractive crystals when the external bias field is absent.
Źródło:
Optica Applicata; 2018, 48, 3; 349-359
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental study of an anomalous hollow beam with orbital angular momentum
Autorzy:
Lu, Xingyuan
Zhao, Chengliang
Hoenders, Bernhard J.
Yang, Yuanjie
Cai, Yangjian
Powiązania:
https://bibliotekanauki.pl/articles/173518.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
anomalous hollow beam
orbital angular momentum
focused intensity
Fourier transform
Opis:
Anomalous hollow beam has potential applications in the optical trapping and free space optical communications, etc. It is noted that, thus far, although a large number of studies have been carried out in this field, most of them are theoretical studies and only quite a few cases have experimental results. Here, we experimentally study the generating of anomalous hollow beam carrying orbital angular momentum, and measure its topological charge. We show that the number of dark rings in the Fourier transform of intensity patterns is equal to the topological charge. The experimental results agree well with the simulations.
Źródło:
Optica Applicata; 2019, 49, 2; 217-226
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low atmospheric density measurement based on Rayleigh scattering of an ultraviolet laser
Autorzy:
Wang, R
Yao, J.
Zhong, K.
Miao, Y.
Cui, H.
Zhao, X.
Zhang, C.
Powiązania:
https://bibliotekanauki.pl/articles/174910.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
atmospheric density measurement
Rayleigh scattering
ultraviolet laser
Opis:
The qualitative measurement of low atmospheric density in the air flow field has been investigated in this paper. The supersonic flow field with Mach number of 1.5 around the NACA0006 aerofoil has been numerically simulated and the transient slight pressure and low density atmosphere have been experimentally determined based on Rayleigh scattering of a 266 nm ultraviolet laser. The scattering patterns have been effectively captured under different atmospheric pressure of 4.5, 92, 470 and 710 Pa with laser energy of only 0.5 mJ. It has been demonstrated that in the pressure range from 4.5 to 1100 Pa, corresponding to the atmospheric density from 4.8105×10–5 kg/m3 to 1.279×10–2 kg/m3, the scattering intensity of an ultraviolet laser is linear to the pressure and density with the slope coefficient of 0.00968 a.u./Pa and 0.83226 a.u./(kg/m3×10–3). It has been proved that Rayleigh scattering is a promising technology for observation of instantaneous and multidimensional distribution of a supersonic flow field.
Źródło:
Optica Applicata; 2013, 43, 3; 597-605
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Colloidal crystal cladded microfiber for refractive index sensing
Autorzy:
Yan, H. T.
Zhao, X Y
Zhang, Ch.
Zhen, Z Q
Li, Q Z
Cao, J X
Xia, L X
Powiązania:
https://bibliotekanauki.pl/articles/174902.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
microfibers
colloidal crystals
refractive index sensing
Opis:
We investigate the evanescent field of a microfiber wrapped by colloidal crystals. The microfiber has the diameter of about 1 μm that is drawn from a single-mode fiber with an alcohol lamp. The colloidal spheres are further attached to the microfiber through thermal evaporation, then they self-assemble to crystal-like structures. The 400 nm, 590 nm, and 710 nm-diameter SiO2 colloidal spheres are used, respectively. The spectral responses are studied theoretically and experimentally, and the results agree with each other. It is revealed that the evanescent field of a microfiber could be modulated by the photonic band-gap of colloidal crystals. This characteristic is very useful in refractive index sensing for liquids.
Źródło:
Optica Applicata; 2014, 44, 2; 309-315
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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