A proposed hybrid model of ANN and KNN for solar cell defects detection and temperature prediction using fuzzy image segmentation.

This paper presents a novel hybrid model employing Artificial Neural Networks (ANN) and Mathematical Morphology (MM) for the effective detection of defects in solar cells. Focusing on issues such as broken corners and black edges caused by environmental factors like broken glass cover, dust, and temperature variations. This study utilizes a hybrid model of ANN and K-Nearest Neighbor (KNN) for temperature prediction.

Closed-form approximation of symmetric thin-film multi-layer plasmonic dispersion equation solutions.

An original asymptotic method is developed and used to find closed-form approximations to the symmetric thin-film three- and multi-layer plasmonic dispersion equations. Closed-form analysis of three-layer metal-insulator-metal (MIM: "M" is metal and "I" is insulator) and IMI devices shows a complementary physics underpinning their properties. Analysis of multi-layer symmetric devices, considered for a seven-layer MIMIMIM example, uncovers a remarkable departure from the physics governing MIM and IMI features.

Dual broadband infrared absorptance enhanced by magnetic polaritons using graphene-covered compound metal gratings.

A dual broadband perfect absorber based on a graphene-covered compound silver (Ag) grating structure working in the infrared (0.8-2.1 µm) regime is proposed and investigated numerically.

Low loss slow light propagation in silicon slot waveguide.

Silicon slot waveguide Bragg gratings have been designed, fabricated and the experimental data has been analyzed for its slow light properties. Slow light with a group index of 12.38 at a wavelength near 1555 nm and having a low propagation loss of 5.

Experimental demonstration of magnetoplasmon polariton at InSb(InAs)/dielectric interface for terahertz sensor application.

We experimentally demonstrate surface plasmon resonance (SPR) in the terahertz range in InSb and InAs. The surface plasmon is excited on the interface between a thin polymer film and the semiconductor using a silicon prism in Otto configuration. The low effective mass of InSb and InAs permits tuning of the SPR by an external magnetic field in the transversal configuration.

Semiconductor-based plasmonic interferometers for ultrasensitive sensing in a terahertz regime.

A robust plasmonic semiconductor-based Mach-Zehnder interferometer (MZI), which consists of a semiconductor layer with a microslit flanked by two identical microgrooves, is proposed and investigated for the terahertz sensing. The microgrooves reflect the surface plasmon polariton waves toward the microslit, where they interfere with the transmitted terahertz wave. The interference pattern is determined by the permittivities of the sensing material and semiconductor (i.

Subwavelength InSb-based Slot wavguides for THz transport: concept and practical implementations.

Seeking better surface plasmon polariton (SPP) waveguides is of critical importance to construct the frequency-agile terahertz (THz) front-end circuits. We propose and investigate here a new class of semiconductor-based slot plasmonic waveguides for subwavelength THz transport. Optimizations of the key geometrical parameters demonstrate its better guiding properties for simultaneous realization of long propagation lengths (up to several millimeters) and ultra-tight mode confinement (~λ/530) in the THz spectral range.

Wavelength-selective emitters with pyramid nanogratings enhanced by multiple resonance modes.

Binary gratings with high or low metal filling ratios in a grating region have been demonstrated as successful candidates in enhancing the emittance of emitters for thermophotovoltaics since they could support surface plasmons (SPs), the Rayleigh-Wood anomaly (RWA), or cavity resonance (CR) within their geometries. This work shows that combining a tungsten binary grating with a low and high filling ratio to form a pyramid grating can significantly increase the emittance, which is nearly perfect in the wavelength region from 0.6 to 1.

Generation of hollow beam with radially polarized vortex beam and complex amplitude filter.

The generation of hollow beams with a long focal depth from a radially polarized Bessel-Gaussian beam with a second-order vortex phase and an amplitude filter is theoretically investigated by Richards-Wolf's integral. The null intensity on the optical axis is achieved by introducing the second-order vortex. The long focal depth is a result of the amplitude filtering based on the cosine function and Euler transformation.

Imperfectly geometric shapes of nanograting structures as solar absorbers with superior performance for solar cells.

The expectation of perfectly geometric shapes of subwavelength grating (SWG) structures such as smoothness of sidewalls and sharp corners and nonexistence of grating defects is not realistic due to micro/nanofabrication processes. This work numerically investigates optical properties of an optimal solar absorber comprising a single-layered silicon (Si) SWG deposited on a finite Si substrate, with a careful consideration given to effects of various types of its imperfect geometry. The absorptance spectra of the solar absorber with different geometric shapes, namely, the grating with attached nanometer-sized features at the top and bottom of sidewalls and periodic defects within four and ten grating periods are investigated comprehensively.

Investigation of optical absorptance of one-dimensionally periodic silicon gratings as solar absorbers for solar cells.

A rigorous design using periodic silicon (Si) gratings as absorbers for solar cells in visible and near-infrared regions is numerically presented. The structure consists of a subwavelength Si grating layer on top of an Si substrate. Ranges of grating dimensions are preliminary considered satisfying simple and feasible fabrication techniques with an aspect ratio defined as the ratio of the grating thickness (d) and the grating lamella width (w), with 0 < d/w < 1.

Imperfectly geometric shapes of nanograting structures as solar absorbers with superior performance for solar cells.

The expectation of perfectly geometric shapes of subwavelength grating (SWG) structures such as smoothness of sidewalls and sharp corners and nonexistence of grating defects is not realistic due to micro/nanofabrication processes. This work numerically investigates optical properties of an optimal solar absorber comprising a single-layered silicon (Si) SWG deposited on a finite Si substrate, with a careful consideration given to effects of various types of its imperfect geometry. The absorptance spectra of the solar absorber with different geometric shapes, namely, the grating with attached nanometer-sized features at the top and bottom of sidewalls and periodic defects within four and ten grating periods are investigated comprehensively.

Ultrashort pulse polarization control in silicon waveguides.

The nonlinear polarization dynamics of ultrashort optical pulses propagating in a low birefringent silicon waveguide is theocratically and numerically studied, with a static electric field applied across the waveguide. It is shown that the pulse shape and polarization evolution can be efficiently controlled by adjusting the magnitude of the applied dc field. It is also demonstrated that the polarization instability regime can be achieved in such waveguides - despite the presence of strong linear losses - by appropriately engineering the spatial distribution of the control field along the waveguide.

Electronic control of soliton power transfer in silicon nanocrystal waveguides.

We demonstrate numerically that the power transfer from one polarization component of a (1+ 1)D vector spatial soliton to the other in a birefringent nonlinear medium can be controlled via the electro-optic Kerr effect by varying the externally applied electric field. We show how several all-optical operations involving fundamental vector solitons can be electronically controlled. We also discover that the split-up of the higher-order vector solitons due to the two-photon absorption (TPA) can be suppressed by adjusting the external electric field.

Electrically and optically controlled cross-polarized wave conversion.

Light wave propagation in third-order nonlinear media with applied external electric field is investigated. Interplay between the nonlinear electro-optic and all-optical effects is examined theoretically. Energy exchange between the orthogonal light polarizations, the cross polarization conversion, results.

Polarization changes of partially coherent pulses propagating in optical fibers.

We consider polarization changes of partially coherent pulses propagating through birefringent dispersive fibers in the linear regime. We show that the evolution of the degree of polarization across such pulses is determined not only by the coherence properties of the pulse in the source plane, but also by the spatial walk-off introduced by the group-velocity mismatch between the two polarization components. The interplay between these two factors determines the asymptotic value of the degree of polarization of an initially unpolarized statistical pulse.

Dark and antidark diffraction-free beams.

We present dark and antidark diffraction-free beams and discuss their properties. We show that all such beams must be partially spatially coherent. The new beams can be used for optical trapping of atoms.