Results in Optics最新文献

We highlighted on the thermal lens (TL) effect of Cadmium Selenide quantum dots (CdSe QDs) using dual beam z-scan technique. The thermal lens nonlinear optical properties of CdSe QDs were investigated by applying the two CW laser beams (λ = 532 nm and λ = 632.8 nm). The thermal lens parameters of the CdSe solutions, such as: the on-axis phase shift (θ), the thermal diffusivity (D), and thermal diffusion time (t_c) were extracted using the theoretical thermal lens model. Our results give new insight into the CdSe QDs dissolved in toluene and are valuable for further development of semiconductor QDs optical devices.

In this study, we successfully synthesized and characterized silicon oxide nanowires/graphene/zinc oxide nanoparticles (SiO NWs/Graphene and ZnO NPs) hybrid nanostructures using pulsed laser deposition (PLD) technique. The characterization of the crystalline phase, morphology, and optical properties of the synthesized hybrid nanostructure systems revealed that the addition of graphene and ZnO NPs led to increased roughness values and changes in the surface topography of the films. The optical properties showed that the addition of graphene and zinc oxide enhanced the reflectivity in specific regions, including the UV and visible ranges, and improved the collection of charge carriers. The SiO NWs/Graphene and ZnO NPs was assessed as a photodetector and exhibited excellent performance, with high quantum efficiency, detectivity, and responsivity in the visible and near-infrared regions, making it a promising platform for the development of next-generation optoelectronic devices in various fields, including security, environmental monitoring, and medical diagnostics.

Stimulated Raman scattering (SRS) is an efficient nonlinear frequency conversion method, enabling simultaneous generation of red, green, and blue (RGB) lasers. In order to synthesize a white light source for laser display by SRS, a 532 nm laser was used as pump source, and high purity gaseous carbon dioxide (CO₂) was used as the Raman active medium. First, by optimizing experimental parameters, with an f = 1.5 m focal lens, in 0.8 atm CO₂ pumped at 304 mJ, a first-order anti-Stokes (AS1) 495 nm blue laser was achieved, with an energy of 31.9 mJ, peak power of 10.9 MW and conversion efficiency (CE) of 10.5 %. Then, Then, the second-order Stokes light (S2) at 624 nm, residual pump laser (S0) at 532 nm, and AS1 laser were utilized as RGB primary colors. By the variation of pressure below 1 atmosphere (atm), the laser-driven white light (LDWL) with adjustable correlated color temperature (CCT) below 4700 K were simulated. Finally, LDWL up to 2.6 × 10¹⁸cd/m² of a CCT of 3300 K could be synthesized at an RGB power ratio of P_R: P_G: P_B = 0.447:0.094:0.459, resulting in a white light power CE of 44.4 % and luminous efficacy of 113.7 lm/W. In addition, use of the 574 nm yellow Raman light is expected to realize a four-primary (RGBY) laser display scheme with higher Luminance and broader color gamut. Moreover, the feasibility of using a 515 nm Yb: YAG laser as pump source to widen the range of CCT and improve the brightness of LDWL was discussed.

In this work, we have determined the χ⁽¹⁾, χ⁽²⁾, and χ⁽³⁾ NLO properties of NH₂substituted aromatic polyenynes in ortho, meta, and para positions. It is worth noting that Mednis-Genkin’s approximation takes into account the intraband contribution with a derivate of the dipole valence-conduction band moment transition, unlike, for example, Ward’s summation-over-sates (SOS) methodology, which considers the difference of these states. Indeed, we have selected these polymers because of the high asymmetry in their molecular wavefunction. In this way, the calculated χ⁽³⁾ values of the para-NH₂ substituted aromatic polyenyne with a higher degree of polymerization are near 1 X 10⁻⁷ esu. For its part, the ortho polymer has higher values, of the order of 1 X 10⁻⁶ esu, due to its high transition dipole moment. We have also found that the energy band distribution in the para position of these polymers produces van Hove points, which have a negligible proportion of the NLO properties, compared with singularity regions 1 and 2, which have a contribution of 100 %. These regions are due to the wavefunction coefficients’ first and second-order derivatives. Besides, without considering border effects nor correlation effects, and only the variation of excitation energy, we have calculated that the quaternary monomeric oligomers of these polymers have almost similar values of χ⁽²⁾ and χ⁽³⁾. Then, it implies building a methodology to synthesize the polymers to avoid canceling the NLO-χ⁽²⁾ and -χ⁽³⁾ values.

This research investigates the potential of flint glass as a foundational material for photonic crystal configurations designed to achieve high nonlinear coefficients across various communication wavelengths. We explore dispersion management within telecom bands using flint glass-based micro-structured optical fibers, employing numerical analysis via the finite element method to assess optical properties. In this study, three different basic MOF structures (hexagonal, square, and octagonal) were created using flint glass background material rather of the commonly utilized fused silica material, and the numerically was assessed in contrast to prior studies and designs. Among the configurations studied, the octagonal arrangement (FGO-MOF) excels in dispersion compensation, achieving −136.6 ps/(nm.km) at 1.55 µm. Conversely, the hexagonal air hole ring cladding design (FGH-MOF) displays higher nonlinearity (770.5 W⁻¹.km⁻¹), a smaller effective area (1.115 µm²), and a high numerical aperture (0.6378). In contrast, the square air hole ring cladding optical fiber (FGS-MOF) exhibits low confinement loss (6.309 × 10⁻⁷ dB/cm) at 1.55 µm but with comparatively less favorable optical properties. Our study demonstrates that the hexagonal microstructured optical fiber with flint glass (FGH-MOF) offers superior performance in dispersion compensation, nonlinearity, and low loss within telecom bands. This finding suggests promising applications in high-bit-rate communication systems, biomedical sensing, and supercontinuum generation, presenting exciting avenues for further research and practical implementation.

This article reports on the development of a new Web-based application software for calculating Judd-Ofelt intensity parameters and derived quantities from the emission spectra of Eu³⁺ doped compounds. The application was entirely developed in JavaScript, and it is compatible with all major browsers. The web application can be accessed via the following link https://sciapps.sci-sim.com/judd_ofelt_analysis_Eu.html. Test samples of ZnO doped with different amounts of Eu³⁺ were synthesized using the combustion method, and their radiative properties and the chemical environment in the Eu surroundings were thoroughly investigated by Judd-Ofelt intensity and the derived parameters using the online application. In contrast to the tediousness and time-consuming process of these types of calculations, by using this online software, all intensity parameters and the derived quantities can be obtained within a short time.

The tremendous speed and security that Free Space Optical Communication (FSOC) technology provides have led to its rapid expansion. This opens up a plethora of possibilities for terrestrial communication with small ranges of up to a few kilometers, such as multi-campus and building-to-building communication. However, the ever-varying nature of atmospheric channels poses a major challenge degrading the optical signal strength. Several constituents of atmospheric channels like fog, dust, smoke, rain, and wind turbulence will influence the performance of an FSOC channel. In this paper, we present a system model focusing on adverse atmospheric channels, primarily by replicating varying fog conditions. Additionally, we showcase the successful real-time implementation of diverse forward error correction (FEC) codes in adverse atmospheric conditions, specifically varying levels of fog, using a dedicated test bed. Our experiments demonstrate the capability to recover erroneous data up to 50% Bit Error Rates (BER). Furthermore, we delve into the selection of suitable FEC codes tailored to different fog conditions, aiming to optimize time efficiency with the encoded bitrate.

This comprehensive review investigates the diverse landscape of blood component detection through the one-dimensional, two-dimensional, and photonic crystal fiber biosensors. Each biosensor, dedicated to specific blood components, is scrutinized in detail, with a focus on key parameters such as Quality Factor (Q) coefficient Loss, Figure of Merit (FOM), and Detection Limit (DL). The study discerns notable advancements in sensitivity and confinement loss within the realm of photonic crystal fiber sensors, attributing these improvements to recent structural modifications. The findings contribute valuable insights into the state-of-the-art techniques employed in blood component detection, paving the way for enhanced biosensor technologies in biomedical applications.

CuS-CuO nanoparticles were prepared by air annealing as-made CuS nanoparticles deposited using spray pyrolysis. The optical, structural, and morphological properties of samples were investigated by UV–VIS Spectroscopy, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM). The XRD analysis of as-prepared sample include two phases CuS and Cu₂S, while annealed films are a mixture of CuS and CuO phases. The dimensions of the CuS crystallites were estimated by Williamson's method on the diffraction peaks (81 nm) while the dimensions of the CuO ones were statistically evaluated via the SEM image (95 nm) and corroborated by Williamson's method on the diffraction peaks (98 nm). SEM study of annealed samples reveals that nanoparticles are monocrystalline. Optical analysis shows more than 80 % transmittance through sample thickness 164 nm in the infrared region and two energy bandgaps of 1.92 and 2.50 eV in the visible region associated with CuO and CuS, respectively. In addition, we observe after several optical excitations that only the UV wavelength of 254 nm gives a tangible electrical response. We understand from the literature that this is only possible through one interpretation of the antenna effect. Optical antennas aim to freely change light rays into local energy. In fact, our sample presents nanoparticles with sizes around 80 nm that show clear absorption through the development of their reproducible resistance that increases with polarization toward saturation after 5 V. Therefore, we propose using prepared nanoparticles in a light-harvesting antenna for artificial photodetector and other optoelectronic applications.

In this study, V₂O₅ nanoparticles were synthesized via facile method by annealing ammonium meta vanadate at 450 °C for 1 h. The resulting nanoparticles were analyzed using X-ray diffractometer, scanning electron microscopy, and transmission electron microscopy to investigate their structural and morphological properties. The optical properties of the prepared samples were examined using UV–VIS spectrophotometry. The XRD measurements indicated an orthorhombic V₂O₅ structure with an average crystallite size of 21.34 nm as calculated using the Debye-Scherrer formula. The synthesized V₂O₅ nanoparticles showed a plate like rod structure with an average size around 55 nm through TEM and HRTEM analysis. The Urbach energy (Eu) of V₂O₅ was calculated to be 1.07ev. The V₂O₅ nano-adsorbents were tested for their effectiveness in the selective removal of MB from an aqueous medium, as well vehicle exhaust and soot of ink from non-aqueous media. During the adsorption process, the impact of several factors including time, adsorbent dose, and different initial concentrations were investigated. Equilibrium adsorption isotherms were evaluated using Langmuir and Freundlich equations. The Langmuir model was found to be a better fit for the adsorption equilibrium, with correlation coefficients of 0.915, 0.904, and 0.912 for MB, vehicle exhaust, and soot of ink, respectively. The experimental kinetic results of V₂O₅ were found to fit the pseudo-second-order model for both aqueous and non-aqueous media with a higher correlation factor indicating chemisorption during the adsorption process.