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Wyszukujesz frazę "infrared" wg kryterium: Wszystkie pola


Tytuł:
Infrared and visible image fusion with deep wavelet-dense network
Autorzy:
Chen, Yanling
Cheng, Lianglun
Wu, Heng
Chen, Ziyang
Li, Feng
Powiązania:
https://bibliotekanauki.pl/articles/2202762.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
infrared image
image fusion
image processing
infrared image enhancement
Opis:
We propose a high-quality infrared and visible image fusion method based on a deep wavelet-dense network (WT-DenseNet). The WT-DenseNet includes three network layers, the hybrid feature extraction layer, fusion layer, and image reconstruction layer. The hybrid feature extraction layer is composed of a wavelet and dense network. The wavelet network decomposes the feature map of the visible and infrared images into low-frequency and high-frequency components, respectively. The dense network extracts the salient features. A fusion layer is designed to integrate low-frequency and salient features. Finally, the fusion images are outputted by an image reconstruction layer. The experimental results demonstrate that the proposed method can realize high-quality infrared and visible image fusions, and the performance of the proposed method is better than that of the six recently published fusion methods in terms of contrast and detail performance.
Źródło:
Optica Applicata; 2023, 53, 1; 49--64
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Material parameters of antimonides and amorphous materials for modelling the mid-infrared lasers
Autorzy:
Piskorski, Ł.
Sarzała, R. P.
Powiązania:
https://bibliotekanauki.pl/articles/175109.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
material parameters
computer simulation
mid-infrared devices
GaSb-based lasers
Opis:
The proper modelling of semiconductor device operation with full complexity of many interrelated physical phenomena taking place within its volume is possible only when the material parameters which appear in each part of the self-consistent model are known. Therefore, it is necessary to include in calculations the material composition, temperature, carrier concentration, and wavelength dependences in electrical, thermal, recombination and optical models. In this work we present a complete set of material parameters which we obtained basing mostly on the experimental data found in several dozen publications. To refine the number of equations, we restrict the material list to those which are typically used in edge-emitting lasers and vertical-cavity surface-emitting lasers designed for mid-infrared emission.
Źródło:
Optica Applicata; 2016, 46, 2; 227-240
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polarization dependent high refractive index metamaterial with metallic dielectric grating structure in infrared band
Autorzy:
Li, Jianmin
Chen, Peng
Fang, Bo
Cai, Jinhui
Zhang, Le
Wu, Yinglai
Jing, Xufeng
Powiązania:
https://bibliotekanauki.pl/articles/2172825.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
metamaterial
high refractive index
infrared band
Opis:
According to the theory of high refractive index of metamaterials, a composite structure of metal dielectric grating was designed to achieve high refractive index in infrared band. Based on the S-parameter inversion algorithm, we extracted the effective permittivity, the effective permeability, and the effective refractive index of the designed metamaterial. By changing the geometric parameters of the composite grating metamaterial structure, the effective refractive index of the designed metamaterial reaches more than 8.0 at the infrared resonance frequency. This is a high refractive index that many natural materials cannot achieve. It is noteworthy that the metamaterial structure has obvious polarization sensitivity. The metamaterial structure has both high refractive index and wideband zero refractive index properties when different polarized light is incident. At the same time, we further investigate the influence of metamaterial geometric parameters on the effective refractive index of metamaterials. Also, we propose a double grating metamaterial structure to obtain more degrees of freedom of metamaterial on the effective refractive index.
Źródło:
Optica Applicata; 2022, 52, 3; 441--460
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mid-infrared polarization beam splitter based on square/circular hybrid air holes with wide bandwidth and ultrashort length
Autorzy:
Zheng, Guang-Ming
Powiązania:
https://bibliotekanauki.pl/articles/2172822.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
polarization beam splitter
mid-infrared
photonic crystal fibre
bandwidth
square air hole
circular air hole
Opis:
A novel mid-infrared polarization beam splitter (PBS) based on GaS is proposed. The high birefringence is achieved by using the cladding structure of alternating arrangement of square and circular air holes as well as introducing double elliptical air holes. The finite element method (FEM) is utilized to investigate the mode coupling characteristics in the proposed PBS. The results show that the highest extinction ratio of 115 dB and shortest length of only 40 μm can be realized at a wavelength of 4 μm. A wide bandwidth of 200 nm ranging from 3.9 to 4.1 μm is obtained.
Źródło:
Optica Applicata; 2022, 52, 3; 345--358
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improved method for passive ranging based on surface estimation of an airborne object using an infrared image sensor
Autorzy:
Mikluc, D. L.
Andric, M. S.
Mitrovic, S. T.
Bondzulic, B. P.
Powiązania:
https://bibliotekanauki.pl/articles/174208.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
infrared sensor
passive ranging
pixel filtration
distance estimation
Opis:
A new method for passive ranging using image size measurements from one sensor has been presented. The method relies on pixel filtration with histogram-based thresholding, followed by intensity and gradient magnitude analysis. Its efficiency and robustness were assessed in real infrared surveillance sequences, and it has proved to lead to better results than non-filtering techniques. The object distance estimation mean relative error does not exceed 3%, which implies that the suggested method enables precise range estimation based on object size measurements. To maximize the benefits of the suggested method, Kalman filter has been included in the algorithm in order to overcome fluctuations of the estimated object size.
Źródło:
Optica Applicata; 2017, 47, 3; 383-394
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical design of a short-wave infrared coded aperture snapshot spectral imager based on Offner–Wynne imaging spectrometer
Autorzy:
Song, Chong
Zhou, Liang
Liu, Zhaohui
Jiang, Kai
Liu, Kai
Powiązania:
https://bibliotekanauki.pl/articles/2086755.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Offner-Wynne imaging spectrometer
CASSI
coded aperture snapshot spectral imager
short-wave infrared
optical design
Opis:
A calculation model to obtain the optimal combination of Offner–Wynne imaging spectrometer parameters to balance the RMS spot radius of the chief ray over the entire field is established. On the basis of the calculation model, an Offner–Wynne imaging spectrometer is designed, and then it is applied in a short-wave infrared coded aperture snapshot spectral imager (CASSI). The optical system of the short-wave infrared CASSI is designed by a combination method of independent design and integrated optimization. The spectral smile and spectral keystone of the optical system which operates in the 900–1700 nm band are respectively less than half a pixel. The focal length of the optical system is 1200 mm, the total optical system length is 775mm, and its average spectral resolution is 16 nm. The optical system offers the advantages of excellent imaging quality, compact optical structure, high optical transmittance, reduced spectral smile and spectral keystone.
Źródło:
Optica Applicata; 2022, 52, 2; 143--161
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wide-angle infrared plasmonic perfect absorber based on graphene-silica grating
Autorzy:
Chen, Fang
Powiązania:
https://bibliotekanauki.pl/articles/1835755.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
plasmonic resonance
graphene grating
optical absorption
plasmonic absorber
Opis:
In this paper, wide-angle infrared perfect absorption has been demonstrated by using a double-layer graphene strip grating coupled with a silicon dioxide grating. Numerical simulation of the finite-difference time-domain method indicates that the perfect absorption can be achieved due to the effective impedance matching, and all the incident electromagnetic energy is confined in the Al2O3 layer between the silver substrate and the graphene strip grating. Dual-band perfect absorption is achieved with the change of strip width or chemical potential of the bi-layer graphene strip grating. It is found that the spectral position of the absorption peak can be tuned by the chemical potential or the width of the graphene strip, and additionally by the size of the proposed absorber. Moreover, the proposed perfect absorber shows excellent absorption stability for a wide range of the incident angle up to ±65°. The proposed absorber may find potential application in tunable double band perfect absorbers in the mid-infrared range.
Źródło:
Optica Applicata; 2021, 51, 1; 87-95
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gold nano-elliptic arrays used in plasmonic waveguides in near infrared spectrum
Autorzy:
Nurmohammadi, T.
Yadipour, R.
Abbasian, K.
Powiązania:
https://bibliotekanauki.pl/articles/174404.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
loss coefficient
group velocity
finite-difference time-domain
Opis:
In this paper, we investigated plasmonic waveguides in near infrared spectrum, especially at original (λ = 1310 nm) and also communication bands (λ = 1550 nm) using gold nano-elliptic rings. It is possible to shift localized surface plasmon resonance, by appropriate geometrical properties, to the desired wavelength. Three-dimensional simulations utilizing the finite-difference time-domain algorithm are used to determine the set of geometrical parameters of gold nano-elliptic rings for exciting localized surface plasmon resonance at 1310 and 1550 nm. Employing different configurations of gold nano-elliptic rings chains, waveguides are designed, with–3 dB transmission loss coefficients and group velocities calculations for different modes. In comparison with circular nanorings, elliptic rings showed better characteristics, such as high electric field enhancements and low loss transmission coefficients.
Źródło:
Optica Applicata; 2018, 48, 3; 489-497
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensitivity enhancement of metamaterial-based surface plasmon resonance biosensor for near infrared
Autorzy:
Pal, S.
Prajapati, Y. K.
Saini, J. P.
Singh, V.
Powiązania:
https://bibliotekanauki.pl/articles/173477.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
metamaterials
sensor sensitivity
reflectance
evanescent field
Opis:
The present study investigates the angular response and sensitivity of a surface plasmon resonance biosensor with metamaterial, by taking the advantage of the remarkable property of metamaterials. The proposed biosensor numerically shows that silver with a metamaterial layer enhances the sensitivity. The thickness of metamaterial and silver layer has been optimized. On comparing these results with a conventional surface plasmon resonance biosensor, it is observed that the sensitivity of the proposed biosensor is improved by introducing the metamaterial. The proposed biosensor has a sensitivity 6.3124 times higher than that of the conventional surface plasmon resonance sensor.
Źródło:
Optica Applicata; 2016, 46, 1; 131-143
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Controllable wavelength conversion based on soliton dynamics in mid-infrared fiber
Autorzy:
Shen, Kangle
Yang, Jian
Zhao, Jiayi
Yang, Xinyu
Yang, Hua
Powiązania:
https://bibliotekanauki.pl/articles/27310109.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
soliton dynamics
photonic crystal fiber
all-optical conversion switches
Opis:
We provide a convenient way to actively control the wavelength conversion of probe waves based on the soliton dynamics in the As2S3 fibers. In this paper, it is found by numerical calculation that wavelength conversion occurs in the frequency domain due to the existence of refractive index barrier. By adjusting the collision position of pump pulse and probe pulse to realize the conversion of probe pulse wavelength, the effect of the power and the incident wavelength of the probe wave on the wavelength conversion are also discussed. This frequency domain conversion is of great use in the mid-infrared region, for example, all-optical conversion switches.
Źródło:
Optica Applicata; 2023, 53, 3; 419--429
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selective infrared absorption and refraction of symmetrical two-layered molecular nanofilms
Autorzy:
Rodic, D
Skipina, B
Pelemis, S. S.
Jacimovski, S. K.
Setrajcic, J. P.
Powiązania:
https://bibliotekanauki.pl/articles/174298.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
nanofilm
excitons
Green's functions
permittivity
absorption
refraction
Opis:
We have supplemented the already formulated microscopic theory of optical properties of very ultrathin molecular films (quantum nanofilms), i.e., quasi 2D systems parallel to XY planes bounded by two surfaces. The exposure of nanofilms to the external electromagnetic fields has resulted in the creation of excitons, but different than bulk ones in one direction perpendicular to surfaces. The analysis of the dielectric response of the system to perturbation of an external electromagnetic field shows that optical properties of these crystalline nanosystems for low exciton concentration of Frenkel’s excitons strongly depend on boundary parameters and the thickness of the film. In addition, the dynamical absorption and the refraction coefficient show a very narrow and discrete dependence of external electromagnetic field frequency, which is the consequence of both resonance and quantum size effects. Influences of boundary conditions on optical characteristics (through the analyses of dynamical absorption and refraction indices) of these nanostructures were specially and in details explored. The emission and the luminescence spectrum of the whole film have been analyzed and the results compared to experimental data show very good behavior and very good coordination.
Źródło:
Optica Applicata; 2013, 43, 4; 641-649
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fast near-infrared palmprint recognition using nonnegative matrix factorization extreme learning machine
Autorzy:
Xu, X.
Zhang, X.
Lu, L.
Deng, W.
Zuo, K
Powiązania:
https://bibliotekanauki.pl/articles/173572.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
extreme learning machine
palmprint recognition
superior speed
support vector machine (SVM)
Opis:
Support vector machine and artificial neural network are widely used in classification applications. Extreme learning machine (ELM) is a novel and efficient learning algorithm based on the generalized single hidden layer feed forward networks, which performs well in classification applications. The research results have shown the superiority of ELM with the existing classical algorithms: support vector machine (SVM) and back propagation neural network. In this study, we firstly propose a novel nonnegative matrix factorization extreme learning machine (NMFELM) to improve the performance of standard ELM method. Then we propose a novel near-infrared palmprint recognition approach based on NMFELM classifier. As the test data, we use the near-infrared palmprint database provided by Hong Kong Polytechnic University. The experimental results demonstrate that the proposed NMFELM method outperforms the standard ELM- and SVM-based methods.
Źródło:
Optica Applicata; 2014, 44, 2; 285-298
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tuning the localized surface plasmon resonance of "core-shell Ag nanoparticles on dielectric substrates" to near-infrared window: applications to surface-enhanced Raman spectroscopy
Autorzy:
Salimian, Sina
Soofi, Hadi
Powiązania:
https://bibliotekanauki.pl/articles/1835800.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
core-shell nanoparticles
plasmonics
Raman scattering
Opis:
In this article, plasmonic characteristics of SiO2-Ag and hollow core Ag nanoparticles placed on dielectric substrates are investigated and tuned to the NIR wavelength spectrum for biological applications. It is shown that by placing the core-shell Ag nanoparticles on a dielectric substrate and exciting the normal plasmon mode of the nanoparticle, it is possible to obtain strong plasmon resonances at wavelengths as long as λ = 700 nm which exhibits a red shift of more than 300 nm compared to the resonance of freestanding pure Ag nanoparticles at which normal plasmon resonance wavelength shows a sensitivity of approximately 100 nm/RIU in respect to the substrate refractive index change. “SiO2-Ag and hollow core Ag nanoparticles on silicon” are optimized to exhibit a strong normal plasmon resonance at λ = 633 nm while preserving the plasmonic field enhancement intact. Finally, a three dimensional substrate for surface-enhanced Raman spectroscopy (SERS) is designed and numerically investigated. The substrate is composed of Si nanorod array decorated with the designed nanoparticles which exhibits superior characteristics such as a uniform and gapless field enhancement and an electromagnetic enhancement factor of more than 3 × 106, an order of magnitude higher than the enhancement factor for a similar structure decorated with Au nanoparticles.
Źródło:
Optica Applicata; 2020, 50, 3; 343-355
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Broadband fluorescence emission and laser demonstration in large mode waveguide structure in Yb3+ doped germanate glass
Autorzy:
Khalid, Mamoona
Powiązania:
https://bibliotekanauki.pl/articles/1835769.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
germanate glass
ultrafast waveguide writing
near-infrared laser operation
high linear refractive index
nonlinear refractive index
Opis:
A stable composition (against crystallization) of germanate glass doped with Yb3+ for mid-infrared laser applications is presented. Broad emission spectrum of Yb3+ was obtained for the fabricated glass. Laser operation was demonstrated in 13 mm long waveguide written in the glass using a femtosecond laser operating at 524 nm center wavelength sending 250 fs ultrashort pulses. The resulting CW laser operated at 1.04 μm in the fundamental mode of the waveguide. The propagation loss through the waveguide was 0.6 dB/cm at 1550 nm for 45 μm diameter of the modified structure. The mode analysis of the developed waveguide structure is also presented in COMSOL Multiphysics to study the electric field distribution through different modes of propagation in the waveguide and the confinement loss associated to them.
Źródło:
Optica Applicata; 2021, 51, 1; 75-85
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of a novel photonic crystal 1.31/1.55 µm bi-band filter for near infrared application
Autorzy:
Lallam, F.
Badaoui, H.
Abri, M.
Fedaouche, A.
Powiązania:
https://bibliotekanauki.pl/articles/173714.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
finite-difference time-domain
FDTD
photonic crystals
waveguide
W1KA
selective filters
Opis:
A novel design of a double selective filter for integrated optics in two-dimensional photonic crystals operating at a wavelength of 1.31 and 1.55 µm is proposed in this paper. We focus particularly on filters transmission and selectivity enhancement. The two-dimensional photonic crystals filters are simulated by using a combination of three cascaded waveguides; these later are conceived by one missing row and with different rods radii for efficient filtering purpose. The properties of these photonic crystal structures are numerically investigated by using the two-dimensional finite-difference time-domain method and the numerical results are given for incident light wave having transverse electrical polarization. A final synthesized filter topology is presented and the maximum of transmission is found around 70% and 60% localized respectively near 1.31 and 1.55 µm wavelengths.
Źródło:
Optica Applicata; 2018, 48, 3; 341-348
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł

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