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A systematic treatment of the influence of the optical feedback (OFB) and the ratio of the radiative and the non-radiative recombination lifetime (τr/τnr) on the relative intensity noise (RIN) and the system dynamics of a semiconductor laser (SL) is presented. We found that the ratio τr/τnr causes a significant change in the intensity of noise, states, and route to chaos of such a system. Laser transit from a continuous wave (CW) to a periodic oscillation (PO) becomes faster in terms of the OFB strength by increasing the ratio τr/τnr. The route to chaos was identified in three distinct operating regions, namely, PO, period doubling (PD), and sub-harmonics (SH), which are dependent on the ratio τr/τnr, and injection current. In the route to chaos regime, the ratio τr/τnr triggers a slight shift in the frequency with reference to the frequency of the solitary laser. At upmost levels of the current, the highest value of the ratio τr/τnr stabilizes the laser and stimulates it to operate in CW or PO. In the strong OFB region, when the ratio τr/τnr increases, the chaotic operation changed to CW or PO operation and RIN is suppressed close to the quantum noise level.

In our simulations, we considered two typical magnetic materials, while the first one includes the 3d-transition metal, such as cobalt which is responsible of the presence of magnetism in pyrochlore structure Rb3CoCl5. The second magnetic material was chosen to have 4f-rare earth metal, namely dysprosium that can induce magnetism in garnet material Dy3Al5O12. A general agreement was found between our results and the previous works. In our calculations, we employed the classical Ising model for the above mentioned realistic materials. We specifically studied the magnetic properties over a range of temperature including the critical temperature and above it. To understand the magnetic phase transition, the effect of magnetic field was involved in the classical Ising model.

We study the emission spectrum and quantum-state fidelity for an atomic system interacting with radiation fields of quantum systems described by power-law potentials. We consider a set of manifold fields that are characterizable by their level-energy differences. They include triangular, infinite, and harmonic potentials as special cases. We present the time evolution of the spectrum and fidelity for this class of potentials with respect to model parameters of the physical system. The results indicate that the spectrum and fidelity during the dynamics are highly sensitive to the value of the photon-transition number and exponent parameter.

In this paper, we investigate the emission spectrum of a two-level atomic system interacting with an optical radiation field based on photon-added coherent states of a pseudo-harmonic oscillator (PACSPHO). Also, the purity of the optical field initially prepared in the PACS-PHO is studied through the evolution of the field entropy. We examine the influence of the intensity-dependent field and the photon-transition number on the dynamic behavior of the emission spectrum and field purity. We explore the link between the field purity and the emission spectrum during the time evolution. Finally, we show how the emission spectrum is affected and changed according to the main physical parameters. We find that there is some kind of correlation between the emission spectrum and the field purity, which will be useful in different applications of quantum physics and spectroscopy.

A quaternary glass system was fabricated via the melting quenching method. The mentioned glass system consists of five samples described by the chemical composition 50B2O3 + 30BaF2 + (20-x)Li2O + xAg2O, 0.0

The purpose of this investigation is to study the physical, structural and optical characteristics of a newly fabricated SrO2 doped lithium bismuth borate glass system. The current glass system was fabricated according to the chemical formula 50B2O3 + 25Bi2O3 + (25-x) Li2O + xSrO2, utilizing the solid state- conventional method. It was noticed that The glass density increased from 4.821 to 5.952 g cm−3 whilst the molar volume was decreasing in the range from 32.93 to 30.44 cm3 mol−1 with increase the SrO2 insertion from 0 (BBLSr0 glasses) to 25 (BBLSr25) respectively. The structure of the fabricated glasses was inspected utilizing X-ray diffraction method which clarified that the insertion of SrO2 didn’t affect the amorphous nature of the tested samples. Furthermore, the UV–vis absorption spectrum was utilized to study the UV absorption characteristics for the fabricated glasses. The UV–vis absorption spectrum showed that the absorption and transition bands increase with insertion of the SrO2 contents. Based on the UV/Vis data, several important optical features were calculated like the energy gap (Eg), Urbach energy (Eu), oscillator energy (Eo) and energy of distribution (Ed). Increasing the SrO2 substitution ratio led to increase the optical properties where the refractive index was found to increase from 3.056 to 5.710.

A very interesting challenge concerns the elaboration of nanowires from organic polymers with the aim to design novel nanoelectronic devices. The new VK-Stilbene copolymer based on organic nanowires was developed and characterized in this context. The VK-Stilbene nanowires were made with a template method by filling nanopores of AOO membranes. The prepared nanowires wereinvestigated by morphological spectroscopy and micro-Raman Rinshaw analysis. The modifications of photoemissive properties from microscopy film to nanowires were described by steady-state optical techniques combinedwith time-resolved photoluminescence spectroscopy. A blue shift of the luminescence are observed in the case of nanowires proceed from structural order and shortening of effective conjugation lengths. Therefore, VK-Stilbene nanowires exhibit a remarkably quasi-exponential long-lived and blue-shifted ascribed to a confinement-effect of intra-chain singlet excitons. Additionally, these nano-objects show an increase in the quantum yield with respect to bulk samples. The acquired optical data confirm that VK-Stilbene nanomaterials may be suitable for nanotechnologies.

In this research, the radiation safety features and the optical properties of novel prepared glass samples with nominal compositions 45P2O5 + 25B2O3 + 20Bi2O3 + (10-x)Li2O+xCdO where x = 0, 2.5, 5, 7.5, and 10 have been studied. The XRD was utilized to exclude the crystal structure nature of the glass samples. The density of the samples increases while the molar volume decreases with the rise of the CdO incrementation ratio. The UV-Vis NIR spectroscopy was utilized to measure the absorbance rate of the fabricated glass sample. Based on the measured absorbance, some important parameters were evaluated, such as the energy gap, Urbach energy, refractive index. The Monte-Carlo simulation code was utilized to evaluate the radiation attenuation properties of the current glass samples in the energy range 0.015 till 15 MeV.

The nanostructured materials from Ag and Au@Ag core/shell bimetallic were synthesized by pulsed infrared laser ablation process in different liquid media technique in just one-pot step. By varying the surrounding media by metallic precursor solution and the laser energy, the monometallic nanoparticles were changed to bimetallic nanocomposites in a form of core/shell structure with tuning their shell thickness. The prepared nanostructured materials were examined by different spectroscopic techniques to inform their physicochemical properties. The characterization techniques proved that the crystallinity of prepared samples. Besides, the bimetallic nanocomposite structure has a core/shell form with Au in the core and Ag in shell. Also, as the laser intensity raises, the Ag-shell’s thickness grows, and the core/shell diameter increases, which was affected in their linear and nonlinear optical properties. Their linear properties were investigated depended on Mie theory. Besides, the nonlinear optical parameters were determined by Z-scan technique, which demonstrated that the nonlinear optical properties of a shell can be tuned depending on their thickness. The prepared core/shell nanocomposites with different particle sizes confirmed the capability for possible application in optoelectronic applications as good optical limiting materials.

This paper reports the tailored visible light emission (blue, green and white) traits of the colloidal silicon quantum dots (SiQDs) integrated with zinc (ZnSiQDs). These QDs were derived from the PSi etched with Zn powder. The ZnSiQDs was prepared via the photo-electrochemical etching process (40 mA/cm2 for 20 min) of the n-type Si wafer immersed inside the solution made from the hydrofluoric (HF) acid to ethanol (ET) volume ratios of 7:1 and 7:3 with the Zn powder (0.17 g) inclusion. The as-prepared samples (named as ZnSiQDs-7:1 and ZnSiQDs-7:3) were characterized to determine the influence of HF:ET on their structure, morphology and optical characteristics. The XPS analyses of the samples revealed the formation of ZnO. The FESEM images exhibited the growth of PSi layer of thickness 8.192 μm and 7.073 μm for the ZnSiQDs-7:3 and ZnSiQDs-7:1 samples, respectively. The EFTEM image analyses showed the nucleation of the ZnSiQDs of average diameter 2.7 nm (for ZnSiQDs-7:3) and 1.33 nm (for ZnSiQDs-7:1). The band gap energy for both samples estimated from the absorption spectra was 3.6 eV. The emission spectra of the studied ZnSiQDs under three different excitation wavelengths disclosed the intense visible peaks (blue, green and white) in the range of 385–700 nm. This observation was mainly ascribed to the effects of quantum confinement and ZnO surface layer on the SiQDs that minimized the silicon oxidation. It is established that by controlling the HF to ET volume ratio the visible luminescence of the ZnSiQDs can be customized, useful for diverse optoelectronic applications.

A series of six tungsten-based bismuth borate glasses with a xWO3- 20 Bi2O3- 20 Na2O2- (60-x) B2O3), 0≤ x ≤ 5 wt% chemical composition were synthesized by using the solid-state conventional method. The structures of the fabricated samples were studied with X-ray diffraction analysis. Optical features such as the energy gap (Eg), Urbach energy (Eu), steepness parameter (S), refractive index (n) and Fermi level energy (EF) were measured for the fabricated glasses with a UV–Vis–NIR spectrophotometer. Furthermore, a Monte Carlo simulation code (MCNP-5) was applied to estimate the gamma ray mass attenuation coefficient (MAC) for the fabricated glasses. The simulated data showed that the insertion of WO3 increases the MACs of the fabricated samples: the highest and lowest MACs were obtained for the W6 and W1 glasses, respectively. Then, the simulated MAC was used to calculate the mean free path (MFP) for all the fabricated glasses. The thinnest MFP was achieved by W6 (increasing from 0.007 to 70,560 between 0.015 and 15 MeV, respectively), while the thickest MFP was achieved by W1 (increasing from 0.0100 to 8.975 between 0.015 and 15 MeV, respectively). Moreover, new Phy-x/PD software was used to calculate MAC, MFP, equivalent atomic number (Zeq) and the exposure and energy absorption buildup factors (EBF and EABF). The simulated and calculated results showed that adding WO3 enhances the shielding properties of the synthesized glass.