Optical and Quantum Electronics最新文献

We synthesized the pristine and MoS₂ QDs coated the UiO-66 nanostructures employing an eco-friendly drop casting method and studied the physical properties of nanostructures by experimental methods. The X-ray diffraction analysis confirmed that all samples exhibit a singular cubic phase with space group Fm3m. The presence of MoS₂ quantum dots coating led to an observed growth in crystalline size and an increase in structural defects. A rise in the optical energy gap (4.02–5.05 eV) and an improvement in transmittance were noted as the concentration of coated MoS₂ quantum dots increased. The film thickness of UiO-66@X%MOS₂ (X% = 0, 10, 15, 20, and 25) was around 140 ± 5 nm and the increase in the concentration of MoS₂QDs was found to be inversely proportional to the decrease in refractive index. The absolute part values of the dielectric constant (ε₁) are more significant than the imaginary part (ε₂). Optical conductivity decreases with the higher content of embedded MoS₂ QDs (from 2.75 × 10¹⁰ to 1.75 × 10¹⁰) at wavelengths 300–250 nm. Thus, MoS₂ QDs-coated UiO-66 nanostructures show suitable potential applications in: optoelectronics, efficient conversion of energy, and numerous other works implemented in the sphere of nanotechnology.

In this research, a new photonic crystal structure for decoding operation with two inputs and four outputs is introduced. A square array of 28 × 45 silicon rods with a lattice constant of 485 nm has been used as the fundamental structure. Two input signals along with a bias signal reach the four output ports via nine waveguides. Four ring resonators are responsible for coupling light to the output ports. In each ring, a 4 × 4 array of nonlinear rods made of doped glass is used. Depending on the light intensity applied to the rings, one of the resonators couples the signal to one of the output ports. The use of ring resonators increases the coupling efficiency and enhances the light intensity at the output ports. As a result, the structure’s contrast ratio reaches 13.71 dB, and distinguishing between logic 0 and logic 1 for digital applications is well feasible. Calculation of the field components shows that its time response is 194 fs, faster than other structures. This attractive feature allows the designed decoder to be implemented in photonic circuits. Furthermore, the structure area is 296 µm² which is smaller compared to ring-based 2-to-4 decoders. Based on the obtained results, it can be said that the presented structure performs better compared to other photonic crystal-based decoders.

Cadmium sulfide thin films are deposited using the thermal evaporation technique and coated with 50 nm thick Sb nanosheets. Both the coated and uncoated films undergo structural, morphological, and optical investigations to explore potential modifications resulting from the Sb coating. The antimony nanosheets successfully increase the crystallite sizes from 28 to 34 nm and decrease the defect concentration from 4.36 × 10¹¹ lines/cm² to 3.02 × 10¹¹ lines/cm². The deposition of Sb nanosheets on CdS films induces the formation of nanowires with a length of 3.0 μm. Sb nanosheet coatings improve visible light absorption by more than nine times, redshift the energy band gap, suppress free carrier absorption in the infrared (IR) range, and increase the optical conductivity of CdS films. Additionally, as optical filters and waveguides, Sb-coated CdS films exhibit a terahertz cutoff frequency range of 0.47–32.06 THz as light energy increases from the IR to ultraviolet ranges. It is also observed that Sb coating alters the third-order nonlinear susceptibility of CdS, making it tunable, more polarizable, and suitable for nonlinear optical applications. Photocurrent measurements showed that Sb nanosheets improved the light responsivity by 330% and significantly enhanced the response time. The enhanced features of CdS achieved through Sb nanosheet coatings position CdS in the preferred group for nonlinear optical waveguides applicable in terahertz and nonlinear optical applications.

The paper considers an algorithm for entangling the states of an exciton qubit on a single quantum dot and a charge qubit on a double quantum dot. The possibility of performing a conditional two-qubit CNOT operation using laser transitions and the Förster effect is analyzed. Estimates of the system parameters are given for which this operation is implemented with a probability close to unity.

This study presents a terahertz (THz) resonance gas sensor design incorporating graphene, black phosphorus, and MXene materials in a metasurface structure. The sensor leverages the unique properties of these advanced two-dimensional materials to achieve enhanced sensitivity and versatility in gas detection applications. The proposed design consists of elliptical and square-shaped resonators arranged on a SiO₂ substrate with a ground plane back reflector. Comprehensive simulations using COMSOL Multiphysics were conducted to analyze the sensor’s performance across various structural parameters and operating conditions. The sensor demonstrates a maximum sensitivity of 400 GHzRIU⁻¹ and a figure of merit up to 0.816 RIU⁻¹ within a refractive index range of 1–1.07 RIU. Electric field distribution analysis validates the sensor’s transmittance response at different frequencies. Notably, the design shows potential for 2-bit encoding applications based on transmittance characteristics under varying graphene chemical potential values. Compared to existing studies, the senso’s performance is particularly better in terms of sensitivity, offering advantages such as room temperature operation and fast response times. This research contributes to the advancement of THz sensing technology and opens new possibilities for highly sensitive and versatile gas detection in various applications.

Our investigation focused on an in-depth examination of the physical properties of KZnH₃ and NaZnH₃, with lattice parameters of 4.04 and 3.72 Å, respectively. Both compounds exist stably in a cubic structure and exhibit metallic behavior with no band gap. At the Fermi level, the total and partial densities of states exhibit a significant conductivity, confirming the metallic behavior. These materials have brittle and anisotropic properties. Because of their greater bulk modulus, average shear modulus, and Young’s modulus, NaZnH₃ appears harder compared to KZnH₃. Optical properties indicate significant absorption and optical conductivity in the energy spectrum of 6–9 eV. NaZnH₃ has a greater static refractive index and reflectivity as compared to KZnH₃. The research on hydrogen storage suggests that both of these materials can store hydrogen, however, NaZnH₃ is a more promising candidate due to its higher hydrogen storage capability.

In this paper, carrier reservoir semiconductor optical amplifiers (CR-SOAs) are utilized for the first time in designing an all-optical 2 × 1 multiplexer with enable function, operating at 120 Gb/s. Traditional SOAs face challenges with slow carrier recovery, restricting their application in high-speed scenarios. CR-SOA, with a carrier reservoir near the active region, replenishes carriers quickly, enabling faster gain and phase recovery. For the first time, a 2 × 1 multiplexer with an enable input is proposed, adding flexibility and control for dynamic data routing in optical systems. Basic gates such as AND, OR, and NOT gates have been designed using this multiplexer, with the enable input enhancing their versatility. The performance of the multiplexer and gates is evaluated using metrics like quality factor, extinction ratio, contrast ratio, and eye opening factor. The quality factor is analyzed concerning parameters such as amplified spontaneous emission, data rate, carrier transition time, and injection current. Simulation results confirm the functionality of the 2 × 1 multiplexer and logic gates, demonstrating satisfactory performance at high data rates.

In this paper, the fractional Chiral nonlinear Schrödinger equation with time-dependent coefficients (FCNSE-TDCs) is considered. The mapping method is applied in order to get hyperbolic, elliptic, trigonometric and rational fractional solution. These solutions are vital for understanding some fundamentally complicated phenomena. The obtained solutions will be very helpful for applications such as optics, plasma physics and nonlinear quantum mechanics. Finally, the influence of the time-dependent coefficients and the conformable fractional derivative order on the exact solutions of the FCNSE-TDCs is presented.

Based on the extended Huygens–Fresnel diffraction integral, the analytical expressions for a finite Airy-Hermite-Hollow Gaussian Beam (FAHHGB) propagating through a gradient-index medium (GRINM) are developed. The characteristics of the normalized intensity for the FAHHGB through the GRINM are theoretically and numerically investigated. The effects of gradient-index parameter β, the mode-orders (beam order (m) and hollow term order (n)), and the Gaussian waist ({omega }_{0}) on the propagation process of the studied beam are numerically discussed in detail. It is found that the normalized intensity distribution of FAHHGB undergo periodic changes during its propagation process in the GRINM. The periodical traits of the normalized intensity distribution of the FAHHGB in a GRINM are strongly affected by the gradient-index parameter. However, the changing of the beam parameters ((m) and (n)) play a clear role in geometrical form of the beam profile in the medium. Finally, the current study included three types of finite Airy Gaussian modes as special cases.

The objective of the present study was to utilize the two-dimensional (2D) structures of silicone (known as silicene) in the structure of solar cells. Its spectacular optical and electronic properties justify its application in solar structures. For this purpose, silicene was involved in the solar cell structure in 3 manners: as silicene1, an n-type semiconductor layer doped with P impurity; silicene2, a p-type semiconductor layer doped with Al; and as the free-standing silicene for the front contact. The former two applications were conducted in the ITO/silicene (1, 2)/(textrm{MoS}_2) (n)/a-SiGe: H (i)/c-Si (P)/Au structure, while the latter was in the Silicene/(textrm{MoS}_2) (n)/a-SiGe: H (i)/c-Si (P)/Au structure. Using the AFORS-HET software, the solar cells were exposed to AM1.5 spectrum radiation at 300 K temperature, and the impacts of 1 sun, 0.1 sun, and 10 sun illumination intensities were evaluated to obtain a better insight into the function of this 2D structure. The highest efficiencies in the mentioned illumination intensities were observed in the proposed cell with the silicene1 layer as the semiconductor, which were 18.96, 17.96, and 19.22%, respectively. Moreover, the efficiencies of the cell with free-standing silicene as the front contact were 27.13, 25.95, and 27.65%, respectively, in the mentioned illumination intensities.