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Wyszukujesz frazę "Wang, W W" wg kryterium: Autor


Wyświetlanie 1-14 z 14
Tytuł:
The kurtosis parameter of partially coherent controllable dark hollow beams in free space
Autorzy:
Li, J.
Wang, W W
Lai, Y
Powiązania:
https://bibliotekanauki.pl/articles/173815.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
kurtosis parameter
partially coherent controllable dark hollow beams
free space
Opis:
Based on the extended Huygens–Fresnel principle and the definition of second-order moments of the Wigner distribution function, the analytical expression for the kurtosis parameter of partially coherent controllable dark hollow beams in free space is derived, and used to study the influence of beam parameters on the kurtosis parameter. It is shown that the kurtosis parameter increases with increasing the wavelength and the waist width, or decreasing the scaling factor, however, the effect of the beam order and the spatial correlation length on the kurtosis parameter depends on the propagation distance. The results can be interpreted physically.
Źródło:
Optica Applicata; 2014, 44, 4; 533-543
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wideband optical frequency comb generation using a fiber re-circulating loop cascaded with a spectrum expander including highly nonlinear fiber
Autorzy:
Wang, F.
Kang, W.
Powiązania:
https://bibliotekanauki.pl/articles/1835772.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical frequency comb
highly nonlinear fibre
cascaded four-wave mixing
Opis:
A wideband optical frequency comb (OFC) generator using a fiber re-circulating loop (FRL) including a phase modulator and optical amplifier, cascaded with a spectrum expander containing a high-power erbium-doped fiber amplifier and highly nonlinear fiber (HNLF) is proposed and experimentally demonstrated, in which the FRL is used as a source to generate seed comb lines, and then generated seed comb lines are extended to a wideband optical frequency comb using cascaded four-wave mixing in the HNLF. Only using one stage spectrum expander, a stable 20-GHz optical comb with 201 comb lines within 30-dB power deviation, spanning 40-nm bandwidth, is achieved. The results show that the HNLF has unique ability to broaden output spectrum from the FRL. In addition, an optical frequency comb is dramatically broadened, which may be predicted by optimizing gain and dispersion of the FRL or configuration of the spectrum expander, or both.
Źródło:
Optica Applicata; 2021, 51, 2; 181-191
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Moving-aperture-based three-dimensional micro-measurement system
Autorzy:
Fan, S.
Yu, M.
Jiang, G.
Wang, Y.
Wang, W.
Li, W.
Powiązania:
https://bibliotekanauki.pl/articles/174026.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical microscopy
computational photography
three-dimensional micro-measurement
moving aperture
Opis:
To overcome the depth-of-field limitation of an optical microscope image, a three-dimensional measurement method with a superior depth-of-field is proposed. In the proposed method, light-field information of different angles is obtained by moving the aperture and the three-dimensional scene is reconstructed by using a computational reconstruction technology. First, stereo matching of different aperture position images is performed to obtain the multi-aperture imaging deviation. The focal plane moving distance is thereby estimated. Then, the relational expression between the image coordinates and the focal plane moving distance is determined according to the image coordinates. Two dimensional coordinates of the space point are obtained by the expression coefficients. Finally, the depth coordinates are computed, and three-dimensional reconstruction of the spatial points is completed. Experiments of three-dimensional measurements of the calibration board with different angles and circuit boards are conducted. The results show that the maximum error of the distance measurement is controlled into 0.84%, and the maximum angle measurement error is controlled into 4.56%.
Źródło:
Optica Applicata; 2018, 48, 4; 533-547
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Converged ultra-wideband and multi-level wired signal downstream transport over single wavelength in wavelength-division multiplexing passive optical network
Autorzy:
Ma, H
Wang, F.
Wang, W.
Zhang, X
Yu, Q.
Powiązania:
https://bibliotekanauki.pl/articles/174929.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
ultra-wideband (UWB)
multi-level amplitude switch keying (M-ASK)
wavelength-division multiplexing passive optical network (WDM-PON)
Opis:
Simultaneous providing services of ultra-wideband and wired signal over single wavelength can greatly decrease the complexity and reduce the costs of a wavelength-division multiplexing passive optical network. However, ultra-wideband signal occupies the spectrum range from 3.1 to 10.6 GHz, and a narrow idle frequency band (from 0 to 3.1 GHz) could be employed to transport wired signal with a limited rate. In this paper, we proposed a scheme to simultaneously provide ultra-wideband and wired services, in which the information rate of the wired signal is enhanced by employing a multi-level amplitude switch keying signal in the idle frequency band formed by ultra-wideband signal. In comparison with other advanced modulation formats used for wavelength-division multiplexing passive optical networks such as orthogonal frequency division multiplexing, multi-level amplitude switch keying signal can be easily received by using intensity modulation direct detection, which will greatly reduce the cost of end-users. Especially, if a multi-band ultra-wideband signal is substituted for the direct-sequence ultra-wideband signal, the available spectrum range to transport wired signal will be easily extended to 5 GHz as multi-band ultra-wideband signal has a narrower spectrum width and flexible center frequency, so 4-amplitude switch keying signal with a rate of 5 Gbaud will achieve an information rate of 10 Gbit/s.
Źródło:
Optica Applicata; 2015, 45, 4; 433-445
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simultaneous measurement of refractive index and thickness for optically transparent object with a dual-wavelength quantitative technique
Autorzy:
Xu, X.
Wang, Y.
Xu, Y.
Jin, W.
Powiązania:
https://bibliotekanauki.pl/articles/174666.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
digital holography
phase measurement
cell measurement
red blood cell
Opis:
We present a new dual-wavelength quantitative measurement approach that can be employed for simultaneously measuring both the refractive index and the thickness of the homogenous specimen. This method is realized by dual-wavelength in-line phase-shifting digital holography, and then the phase images are obtained by using four-phase step algorithm for each wavelength separately. Based on computer simulation technology, the feasibility and the effectiveness of our proposed method are demonstrated by comparing our simulation results with the experimental results of the spherical silica bead and the red blood cell, respectively. Our work will provide some guidance in the experimental research for transparent phase objects.
Źródło:
Optica Applicata; 2016, 46, 4; 597-605
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three-port beam splitter based on a sandwiched grating with an improved aspect ratio
Autorzy:
Shu, W
Wang, B
Li, H
Li, W
Chen, L.
Lei, L.
Zhou, J.
Powiązania:
https://bibliotekanauki.pl/articles/174445.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
aspect ratio
sandwiched grating
three-port beam splitter
Opis:
In this paper, a fused-silica transmission grating used as a three-port beam splitter is designed by using the rigorous coupled-wave analysis, which is based on the sandwiched grating structure at the wavelength of 800 nm under normal incidence. Firstly, it is feasible to realize such a grating with the prescribed grating duty cycle and grating period. Next, high efficiency can be also achieved for both TE and TM polarizations. Moreover, the aspect ratio of the grating depth to the ridge width can be improved, which is significant for practical applications. At last, the three-port beam splitter is designed with a covering layer on the surface, which can extend its life service.
Źródło:
Optica Applicata; 2015, 45, 3; 279-284
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-parameter measurement under fiber bending based on directional resonance coupling in photonic crystal fibers
Autorzy:
Tan, C.
Wang, Q.
Ding, Y.
Li, H.-W.
Wang, M.
Liu, H.
Powiązania:
https://bibliotekanauki.pl/articles/174320.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fiber bending
multi-parameter measurement
photonic crystal fiber
fiber sensing
Opis:
A multi-parameter sensor with enhanced sensitivity based on magnetic fluids infiltrated photonic crystal fiber is proposed. The sensing performances are investigated using the mode coupling theory and finite element method. Four symmetrical defective channels are assembled into the photonic crystal fiber to produce two resonant transmission dips λCV and λCH in vertical and horizontal directions, respectively. Each dip can be split into two relatively shallow dips (λCV1, λCV2 or λCH1, λCH2) when the photonic crystal fiber is bent. Interestingly, the values of (λCH2 – λCH1) and (λCV2 – λCV1) are associated with corresponding bend-curvature but almost unaffected by external temperature or magnetic field. On the contrary, the values of (λCH2 + λCH1)/2 and (λCV2 + λCV1)/2 are sensitive to temperature or magnetic field regardless of the bending condition. Based on above characteristics and the dependence of the magnetic fluids refractive index on temperature and magnetic field, the proposed sensor can measure not only the bend-curvature and bend-direction, but also the temperature and magnetic field.
Źródło:
Optica Applicata; 2018, 48, 3; 449-462
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polarization-independent metal-dielectric grating with improved bandwidth
Autorzy:
Wang, B
Li, H
Shu, W
Li, W
Li, C
Lei, L
Zhou, J
Powiązania:
https://bibliotekanauki.pl/articles/174684.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
rigorous coupled-wave analysis
reflective efficiency
improved bandwidth
Opis:
A polarization-independent reflective grating with improved bandwidth is presented based on the mixed metal-dielectric grating. The novel grating is composed of the substrate, the metal slab, two dielectric layers, and the covering layer. The grating parameters are optimized for the special duty cycle of 0.6 at an incident wavelength of 1550 nm used in dense wavelength division multiplexing (DWDM). With the designed grating, high efficiency can be diffracted into the reflective –1st order for both TE and TM polarizations, where the polarization-independence is exhibited. Most importantly, the efficiency of more than 90% can be achieved within the incident wavelength bandwidth of 1262–1686 nm, where the bandwidth is improved greatly compared with the reported surface-relief single-layer grating. The reflective grating can have advantages of high efficiency, polarization-independence, and wide bandwidth, which should be useful for DWDM applications.
Źródło:
Optica Applicata; 2015, 45, 1; 71-77
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:
A simple model of the scanning near-field optical microscopy probe tip for electric field enhancement
Autorzy:
Wang, Y.
Cai, W.
Yang, M.
Liu, Z.
Shang, G.
Powiązania:
https://bibliotekanauki.pl/articles/174091.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
near-field tip
electromagnetic field enhancement
finite-difference time-domain
FDTD
Opis:
In this paper, we present a simple near-field probe model that is composed of an elongated ellipsoid and a finite metal truncated cone. The elongated ellipsoid has been shown to act as a protrusion or separate particle near a truncated cone apex with strong near-field enhancement under laser excitation. By controllably varying the length of the ellipsoid protrusion from the truncated cone, the truncated cone-ellipsoid probes can be adapted to the suitability of near-field probes. The effects of substrate material and excitation wavelength on the near field enhancement for different tip apexes are also discussed. In addition, we compared the properties of the truncated cone-ellipsoid probe with the widely used hemisphere conical tip by launching surface plasmon polaritons on plasmonic waveguides to prove the suitability of the truncated cone-ellipsoid probes as high performance near-field probes. The present simple model would provide a theoretical basis for the actual construction of probes.
Źródło:
Optica Applicata; 2017, 47, 1; 119-130
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Highly-efficient three-port output by metal-mirror-based grating
Autorzy:
Li, H.
Wang, B.
Shu, W.
Chen, L.
Lei, L.
Zhou, J.
Powiązania:
https://bibliotekanauki.pl/articles/174526.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
three-port output
metal-mirror-based grating
rigorous coupled-wave analysis
Opis:
A highly-efficient three-port output of metal-mirror-based grating is proposed in this paper. The metal-mirror-based grating can function as a beam splitter which can diffract the normal incident wave into the 0th and the +/- 1st orders for both TE and TM polarizations with the usual duty cycle of 0.5. The analysis of the grating parameters can be optimized by rigorous coupled-wave analysis. The high efficiency for TE and TM polarizations shall be realized. By means of the numerical simulation, the depth and connecting layer thickness of grating can be accurately calculated. The efficiency of per port is near 33.3%, so the novel three-port output grating with a connecting layer would be an excellent optical element.
Źródło:
Optica Applicata; 2016, 46, 1; 87-92
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical investigation of vanadium oxide film with surface microstructure
Autorzy:
Hong, W.
Wang, Z.
Chen, Q.
Sheng, C.
Gu, G.
Luo, P.
Xie, Y.
Powiązania:
https://bibliotekanauki.pl/articles/174416.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
vanadium oxide
VO2
film
surface microstructure
photonic band edge
dispersion material
Opis:
This paper presents a method to design a surface microstructure of vanadium oxide to enhance optical absorption. This method, using a density of eigenfrequency, can be calculated by a planar wave expand method, to indicate the absorption efficiency of a dispersion material, which can be used as an approach method for further design. Based on this, a nanostructure-based vanadium oxide film is designed and simulated to validate this method. The simulation results show that the tendency of density of eigenfrequency is corresponding to the tendency of optical absorption enhancement. Moreover, this structure can achieve high optical broadband absorption when the material dispersion is considered. High optical absorption enhancement can be achieved by adjusting the geometrical parameters; our maximum overall enhancement absorption ratio was 31.84% at the metal phase, which can be attributed to the enhancement effect of a photonic band edge.
Źródło:
Optica Applicata; 2017, 47, 4; 601-609
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mitigation scratch on fused silica optics using CO2 laser
Autorzy:
Liu, C.-M.
Yan, Z.-H.
Yang, L.
Jiang, Y.
Zu, X.-T.
Wang, H.-J.
Liao, W.
Yuan, X.-D.
Zheng, W.-G.
Powiązania:
https://bibliotekanauki.pl/articles/174978.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
mitigation
scratch
fused silica
CO2 laser
Opis:
The scratch on a fused silica surface was treated as a chain of connected damage sites and mitigated one after another using CO2 laser irradiation. The optical microscopy image shows that a scratch with the width of about 30 μm and length of several millimeters can be completely mitigated without the formation of debris and bubbles. The mitigated scratch can survive under raster scan laser irradiation with the fluency increased up to 11.0J/cm2 at 3ns and 351nm. On the contrary, the substrate without CO2 laser mitigation is seriously damaged under this irradiation. The light modulation induced by mitigation is much smaller when the scratch is mitigated before being damaged. The light modulation is about 2 when the distance to the mitigated sample is larger than 20cm. The birefringence induced by residual stress in the mitigated scratch is measured. The retardance of the mitigated scratch before being damaged is not visible. Therefore, residual stress in this mitigated scratch before being damaged should be not a critical potential risk in laser damage.
Źródło:
Optica Applicata; 2016, 46, 3; 387-397
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase features of several typical blood cells and their identification without unwrapping
Autorzy:
Wang, Y.
Chen, Y
Lü, C.
Shang, X.
Xu, Y.
Wu, H.
Zhu, X.
Jin, W.
Powiązania:
https://bibliotekanauki.pl/articles/173588.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
digital holographic phase
nucleated cell
phase model
wrapped phase features
identification
Opis:
The digital holographic phase microscopy (DHPM) technique which has been proposed for cellular morphology and dynamic analysis yielded highly desirable results. However, for nucleated cells (especially white blood cells (WBCs)), their submicroscopic structure has not yet been deconstructed through a phase unwrapping method due to the heterogeneity of an internal phase. By analyzing the phase heterogeneity of subclasses of WBCs, the typical phase models of them are built first in this paper; using the simulation method, the wrapped phase distributions of these models are obtained. However, by optimizing the wrapped phase maps and analyzing the relationships between them and typical blood cells, their features are selected and extracted. Then the models built are sorted out from each other successfully without unwrapping via analyzing these extracted features, which provides a valuable approach and technological base for the classification and identification of blood cells.
Źródło:
Optica Applicata; 2013, 43, 3; 505-514
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-14 z 14

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