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Porous silicon (Psi) has recently attracted considerable attention because of its unique optical and structural properties and capacity to be used in various applications. Due to the importance of this material, we have investigated the infiltration of trivalent erbium ions (Er3+) into silicon-generated pores using the electrochemical approach. The infiltration of Er3+ ions will be done simultaneously with the forming of porous silicon films on p-type (100) silicon substrates. Generating the porous layer can improve the evenness and integration of Er inside the material. During infiltration, Er3⁺ ions can also undergo reduction or co-deposition with other elements at the cathode. The infiltration studies were conducted while subject to the influence of the current density (15–30 mA/cm2). The results showed that the emission of photoluminescence in porous silicon filled with erbium was caused by the presence of Er silicate and Er oxide that developed within the silicon pores during the electrochemical reaction. The reason for introducing rare earth ions is their exceptional optical characteristics, encompassing distinct emission lines and extended lifespan. We comprehensively investigate infiltration and outline the electrochemical etching parameters necessary to create porous silicon. Rare earth ions exhibit exceptional optical luminescence characteristics, displaying a diverse spectrum of optical spectra over the infrared, visible, and ultraviolet regions. [ABSTRACT FROM AUTHOR]

The aim of this research is to investigate novel compositions of oxyfluoride glasses doped with Neodymium (Nd3+) rare earth ions in the visible spectrum. This area has not been extensively studied in the existing literature, so it is vital to understand the favorable photoluminescence characteristics within this part of the electromagnetic spectrum. Therefore, we synthesized and characterized SiO2‐PbO‐PbF2 (SPF) doped with 1% neodymium (Nd3+) ions glasses. Spectroscopic analyses, based on Judd–Ofelt theory, were conducted on absorption spectra. These analyses enabled to determine absorption cross‐sections, transition probabilities, and Judd–Ofelt intensity parameters Ω2, Ω4, and Ω6 for the different transition. Additionally, we calculated various radiative properties, such as branching ratios, integrated cross‐sections, radiative lifetimes, emission cross‐section, optical gain, and the multicolor behavior (chromaticity coordinates, CIE diagram) under different excitation wavelengths. The results suggest promising prospects for using these oxyfluoride silicate glasses doped with Nd3+ as a fluorophore, potentially for lasing materials around 630‐nm emission and in other photonic applications. [ABSTRACT FROM AUTHOR]

Recently, many studies have examined filters for reducing or removing speckle noise, which is inherent to different images types such as Porous Silicon (PS) images, in order to ameliorate the metrological evaluation of their applications. In the case of digital images, noise can produce difficulties in the diagnosis of images details, such as edges and limits, should be preserved. Most algorithms can reduce or remove speckle noise, but they do not consider the conservation of these details. This paper describes in detail, the different techniques that focus mainly on the smoothing or elimination of speckle noise in images, as the aim of this study is to achieve the improvement of this smoothing and elimination, which is directly related to different processes (such as the detection of interest regions). Furthermore, the description of these techniques facilitates the operations of evaluations and research with a more specific scope. This study initially covers the definition and modeling of speckle noise. Then we elaborated in detail the different types of filters used in this study, finally, five statistical parameters such as Root Mean Square Error (RMSE), Mean Square Error (MSE), Structural Similarity Index (SSIM), Peak Signal to Noise Ratio (PSNR), Signal to Noise Ratio (SNR) are calculated, compared and the results are tabulated, common in filter evaluation processes. Trough the calculation of the statistical parameters, we can classify the filters in terms of perceptual quality by providing greater certainty. [ABSTRACT FROM AUTHOR]

The aim of this research is to investigate novel compositions of oxyfluoride glasses doped with Neodymium (Nd 3+ ) rare earth ions in the visible spectrum. This area has not been extensively studied in the existing literature, so it is vital to understand the favorable photoluminescence characteristics within this part of the electromagnetic spectrum. Therefore, we synthesized and characterized SiO 2 -PbO-PbF 2 (SPF) doped with 1% neodymium (Nd 3+ ) ions glasses. Spectroscopic analyses, based on Judd-Ofelt theory, were conducted on absorption spectra. These analyses enabled to determine absorption cross-sections, transition probabilities, and Judd-Ofelt intensity parameters Ω 2 , Ω 4 , and Ω 6 for the different transition. Additionally, we calculated various radiative properties, such as branching ratios, integrated cross-sections, radiative lifetimes, emission cross-section, optical gain, and the multicolor behavior (chromaticity coordinates, CIE diagram) under different excitation wavelengths. The results suggest promising prospects for using these oxyfluoride silicate glasses doped with Nd 3+ as a fluorophore, potentially for lasing materials around 630-nm emission and in other photonic applications., (© 2024 John Wiley & Sons, Ltd.)