Results in Optics最新文献

This study explores the impact of CaTiO₃ and LiNbO₃ crystals on the optical and dielectric properties of polyvinylidene fluoride (PVDF) films. Our investigation employs UV–Visible Spectroscopy to characterize the n-π* C-F related electronic transition within the PVDF matrix. We find that CaTiO₃ crystals significantly decrease the composite’s band gap and dielectric properties, enhancing its electronic and optical attributes. Conversely, LiNbO₃ crystals increase the band gap energy. These variations align with observed DC conductivity changes, suggesting novel functionalities for optoelectronic, sensing, and energy storage applications.

In this article, we used modern technologies to teach the topic of nanomaterials and nanotechnologies. One of the main tasks of the development of modern nanotechnologies and nanomaterials is one of the main tasks of the development of nanoscale solid, liquid and gas phase structures and systems.

A new geometrical vision for a graphene-based THz wave absorber is investigated in this work. A high-performance THz absorber is proposed to exploit complementary conventional periodic arrays of graphene disks. The equivalent circuit model is modified to take account of the complement pattern. The absorber works in two different operational modes based on chemical potential values. One mode shows absorption around 1 THz while the other one expresses perfect absorption at 6 THz and 9 THz. Such a considerable shifting ability via gate stimulations makes the proposed absorber an ideal block for reconfigurable metasurface. The comparison between the circuit model and full-wave simulation verifies an excellent match while ample sensitivity analysis are reported to show the reliability of the proposed switchable THz absorber.

In this article we define Discrete SUPPOSe, a new and faster version of the single shot super resolution SUPPOSe (Superposition of virtual point sources) method. The SUPPOSe method for super-resolution of fluorescent microscope images relies in assuming that the sample source distribution can be modeled as a superposition of virtual point sources of equal intensities distributed in a continuous space, converting the ill posed deconvolution problem into a well posed one. In this work we present a faster new method that consists on discretizing the continuum problem, using a normalized covariance instead of a ${\chi }^2$ for the fitting function and hence transforming the convolution (the main computational time) into a multiplication, and modifying the mutation step of the genetic algorithm. We compare precision, accuracy, resolution and computation time. It is also shown that despite the spatial discretization in Discrete SUPPOSe similar figures for precision, accuracy and resolution are obtained. The algorithm was implemented in Matlab running on a CPU obtaining with a speed improvement factor of more than 15 for one image of 48 × 48 pixels. Processing images in parallel in a 16 cores CPU a 1Mpixel image is computed 240 times faster than the standard SUPPOSe in a 2600 core GPU. Experimental images were used to validate the method.

The innovative, affordable assembled visible spectrophotometer employed in this study aims to analyze the absorption and emission of colorful metallic blends of colorful samples solution. It features a tungsten white light bulb source, an ammeter as a detection element, a digital voltmeter, a diffraction grating for light dispersion, a converging lens for light collimation, and filters of various wavelengths (blue, red, yellow, and yellow-green). The light bulb source was powered by a standard supply set at 6 V. Using metallic solutions of chromium chloride (CrCl₃) and copper sulphate (CuSO₄) with different filter wavelengths, the performance was assessed. The transmittance and absorbance of these metallic solution samples exhibit a linear relationship with approximately 3 % deviation compared to results from a commercial UV–VIS spectrophotometer (DR-6000). Similar investigations were conducted with equivalent quantities of CuSO₄, CrCl₃, and nickel chloride (NiCl₂) solutions, showing a discrepancy ranging from 2 % to 8 % when compared with the commercial UV–VIS spectrophotometer. Therefore, in low-income countries like Ethiopia, colorful metallic solution samples can be effectively analyzed using the newly designed low-cost spectrophotometer.

A novel technique was created to quickly evaluate the impact of various ratios on the efficiency of up-conversion emission using a combination of up-conversion nanophosphors (UCNPs) and gold nanoparticles (Au NPs). Four different types of Y₂O₃ UCNPs with different Er³⁺ or Er³⁺/Yb³⁺ doping, which affects the emission colour as well as the up-conversion mechanism, were prepared via the microwave-assisted hydrothermal method. Au NPs were produced independently using the reduction technique. Different ratios of UCNPs were mixed with the Au NPs in water. The mixed powder composites were extracted for analysis. X-ray powder diffraction was utilized to study the structure of UCNPs with and without Au NPs, while transmission electron microscopy was used to study the morphology and size of Au NPs. Absorption and up-conversion measurements were also made. The novel protocol allowed rapid evaluation of four different Y₂O₃ UCNPs of Er³⁺ and Er³⁺/Yb³⁺ doped with concentrations optimized for red and green emission over a range of Au/UCNP concentrations, which might usually be done in four separate studies. Despite the wide range of variables, only a decrease in UC emission was measured in the presence of Au NPs, suggesting that the conditions for plasmonic enhancement are limited and not easy to attain. In spite of this, in many phosphor/metal NP systems, the innovative prototyping process can enable quick assessment of possible plasmonic enhancement.

Single photon avalanche diode (SPAD) is used in quantum detectors. Quantum detectors are widely used in quantum communication. The quality of these detectors strongly affects the optimal performance of the system. The quality of single photon detectors depends on various parameters, which are usually presented in the SPAD specification. If these detectors are made by the manufacturer or evaluated by the user, there is a need for a method to determine and check its main parameters. In this paper, a simple test setup for extracting some of important parameters has been designed and introduced, which can be used practically. These parameters include Dark Count Rate (DCR), Photon Detection Efficiency (PDE), AfterPulse Probability (APP) and Dead time. In the presented design, an FPGA chip is used to measure the parameters. FPGA is responsible for the simultaneous control of the single photon source and the detector. The presented methods specify how to extract the desired parameters. The characterization methods and detailed formulas presented in this paper calculate SPAD parameters.

A viable solution to detect the one-way speed of light anisotropy in linear motion is by using an Isosceles triangle-shaped design for the experimental setup, from which two light pulses from both ends of one of the triangle’s sides are sent to the same clock upon the detection of the incident and the reflected pulse, thereby evading the need for synchronization. The relativistic effects are taken into account in the timing measurements by incorporating the Lorentz transformation equations of length contraction and time dilation, which produces a non-null result for the time difference of the incident and the reflected pulse, and testing the equivalence of the one-way speed of light with the average of the roundtrip speed, independent of Einstein’s synchronization convention.

With the increasing demand for image transmission in various fields including medical, military and multimedia, the security of information contained on these images has become a standing problem.. This work provides information security for images transfer for 160 Gbps over 140 km optical fiber link. Image encryption and decryption is maintained by applying blowfish algorithm via MATLAB software with the adaption of OptiSystem software to examine data transmission over 16 channels WDM system.. The proposed algorithm has provide a large key space, resistivity to differential attacks, anti-differential attack, brute-force attack and less correlation between adjacent pixels However, channel dispersion and signal attenuation has been controlled with the adaption of symmetric dispersion compensation map and an erbium doped fiber amplifier (EDFA) at the end of the fiber link. Our WDM system design has reached a high figure of merit of about 22,400 as compared with different previous schemes. Moreover, to provoke the power of the proposed cipher algorithm, key space, correlations, histogram analysis and different security analysis has been studied and compared with other algorithms.

This article introduces a novel two-dimensional photonic crystal biosensor designed for the detection of various cancer cell types and the verification of associated parameters. The proposed structure features a circular resonator nanoring with a sensing region at its center, facilitating the connection with cancer cells. The sensor has been tested with a diverse range of cancer cell types including skin, cervical, blood, adrenal, and two subtypes of breast cancer cells (Sort 1 and Sort 2). All outputs of the structure were studied at two different wavelengths and its parameters were analyzed separately. The best quality factor obtained for normal and abnormal cells of the target structure is 13,353 and 3053, respectively. Due to its high-quality factor and high FOM and low DL, this sensor has an acceptable sensitivity of 214.28(nm/RIU). FOM and DL in this sensor are equal to 172.35(RIU⁻¹) and 5.80 × 10⁻⁴(RIU), respectively. The resonant wavelength shift of this structure is a relatively good value due to the coupling distance between the input wave and the resonator nanoring.