Optical and Quantum Electronics最新文献

A novel third-order organic nonlinear optical (NLO) material with promising excellent properties is crucial for NLO applications. For the first time, high NLO active 2-amino-4-methylpyridinium 5-sulfosalicylic acid (2A4MP5SSA) has been rationally designed and single crystals have been grown by the slow evaporation solution growth technique (SEST). X-ray diffraction analysis revealed that 2A4MP5SSA belongs to the category of triclinic system and has a Centro symmetric space group of P1. Remarkably, the grown crystal exhibits competitive and even superior physical properties including high thermal stability and wider transparency than the standard NLO single crystals. The morphology of the as-grown 2A4MP5SSA crystal was equivalent to the theoretically produced morphology. Fourier transform infrared spectroscopy (FTIR) was used to investigate the molecular vibrations of 2A4MP5SSA. The optical characteristics of 2A4MP5SSA recorded using optical transmittance spectrum reveals that the 2A4MP5SSA crystal possesses good optical transparency in the range between ultraviolet (UV) and near-infrared (NIR) regions. Intriguingly, the short cut-off edge of the grown crystal is found to be about 356 nm which is more favourable for developing modern photonic and optoelectronic device applications. The Laser Damage Threshold (LDT), were investigated to understand its effectiveness to be utilized in the area of optoelectronics and photonics. The thermal and mechanical stability of 2A4MP5SSA was tested using Thermo gravimetric Differential Thermal Analysis (TG–DTA) and Vickers hardness test. The third-order nonlinear optical properties of 2A4MP5SSA single crystals were analyzed, which involves studying the absorption coefficient and refractive index behaviour using a continuous wave laser. The grown crystal exhibits outstanding third-order NLO response and wide LDT, which are crucial characteristics for developing practical NLO devices. There are various 2-amino-4-methylpyridine (2A4MP) derivative single crystals available in the literature. However 2A4MP5SSA crystal has not been reported earlier. The findings consequently open a novel path for the logical design of enormous, thermally stable and NLO-active organic complexes for true NLO applications.

Residual stresses adversely influence the strength of polymeric composites and could result in premature failure, warpage, delamination, and matrix cracking. Therefore, residual stress measurement is necessary to predict their effects on the performance of polymeric composites. The primary focus of this study is to compare the performance of the fiber Bragg grating (FBG) sensor for residual stress measurement with that of the digital image correlation (DIC) and strain gauge which are the most commonly used methods in this field. This comparison is of significant importance as it can provide valuable insights into the effectiveness of these techniques in measuring cure-induced residual stresses in polymeric composites. The incremental slitting process was conducted to compare the accuracy and the performance of the FBG sensor with the DIC and strain gauge. The residual stresses were also evaluated using the classical lamination theory (CLT). The 2% difference was achieved between the recorded data by FBGs before and after slitting. The present study also involves monitoring the curing cycle and determining the created residual strains at the end of this process using the FBGs without resorting to destructive methods such as hole-drilling or slitting.

This research work represents a comparative study of the regular n-i-p heterojunction structure ofCs₂TiBr₆ single halide Perovskite solar cells (PSCs) using the SCAPS-1D software framework under ambient conditions.We have studied the performance optimization of different hole transfer layers (HTLs)P3HT, CuO, Cu₂O, and MoO₃ respectivelyfollowed by optical, and electronic properties analysis to identify the appropriate HTL for the FTO/TiO₂/Cs₂TiBr₆/HTL/Ag-based PSC module.Other performance parameters, C-V (Capacitance–voltage), and M-S (Mott-Schottky) plot analysisshows thatMoO₃HTL has better photovoltaic (PV) performance characteristics. Cs₂TiBr₆/MoO₃ based PSC shows higher open circuit voltage (V_OC = 0.2434 V), power conversion efficiency (PCE = 4.8%)compares to Cs₂TiBr₆/ P3HT, Cs₂TiBr₆/CuO, Cs₂TiBr₆/Cu₂O based PSC. On the other look, investigated PSC material Cs₂TiBr₆/MoO₃has shown visible light emission edge at 190 nm wavelength, superior semi-circular shape, higher PV parameters in the context of variation in relative permittivity, carrier lifetime, diffusion length, and defect density at the interfaces.The optimized carrier lifetime of Cs₂TiBr₆/MoO₃-based PSC has been recorded as 50 ns at 500 nm thickness of active material.

Designing an electromagnetic radiating element that can enhance the capacity of a device operating with multiple frequencies simultaneously, while maintaining its compactness and compatibility with customer premise equipment, is a significant challenge. To tackle this issue, this work proposes a multiple input multiple output (MIMO) antenna with eight elements placed 45° apart on a Rogers 5880 substrate which has been micromachined from sixteen edges with a thickness of 0.252 mm. The substrate measures the area of 717.46 mm² boasting a dielectric constant of 2.2 and loss tangent of 0.0009 with a unique star shape. The slot technique improves the return loss accompanied by defected ground structure to achieve dual-band operation at 28.1 GHz (n261) with the impedance bandwidth from 27.95 to 28.4 (0.45 GHz) and 39.5 GHz (n260) having impedance bandwidth from 38.6 to 40.4(1.8 GHz). The inter-element isolation of more than 60 dB is achieved for both bands with micromachined substrate. The measured gain at 28 GHz is 7dBi and at 39 GHz it is obtained as 7.4dBi. The 8-port MIMO is simulated for all the diversity metrics such as Diversity Gain (DG), Channel Capacity Loss (CCL), Envelope Correlation Coefficient (ECC), Mean Effective Gain, Total Active Reflection Co-efficient (TARC). The parameters evaluated for all eight ports are within the standard values with ECC of < 0.001, DG > 9.99 dB, CCL < 0.1b/s/Hz, and the TARC < − 10 dB. The MIMO has been fabricated and tested for various results which favourably aligned with the simulated results validating the applicability of the proposed mm-Wave 8-port MIMO antenna for practical 5G applications. Furthermore, the 8-port is also simulated for conformality check which showed a minor change in impedance bandwidth at 15°, 30°, and 45°. The Specific Absorption Ratio (SAR) analysis has provided values less than 1.6 W/kg for both the intended bands. The conformal and SAR analysis has added an advantage to the application of the proposed antenna for 5G as well as for wearable on-body applications.

This research focuses on a Four-Port dual-band (FPDB) MIMO antenna in millimeter-wave applications. The antenna is compact occupying an overall dimension of 12 × 11 mm² printed on Rogers-Dielectric 2.20 utilizing opposite surface for the printing of radiating patch and ground. An elliptical slotted square patch is used to achieve 28.0 GHz resonance and by scaling the antenna patch by a factor of 0.72, the resonance shifts to 38.0 GHz with additional resonance at 28.0 GHz achieved by embedding rectangular-stub. For better matching of impedance, the antenna is inset-fed and the four-port configuration achieves measured operating bandwidth of 26.32–29.76 GHz and 36.82–38.89 GHz. The proposed MIMO antenna includes desirable 2-D radiation patterns in the Elevation and Azimuth plane with a peak gain of 6.77dBi at 28.0 GHz and 9.46dBi at 38.0 GHz. The measured diversity parameters include ECC < 0.0056, DG (cong ) 10.0 dB, TARC < − 10.0 dB, CCL < 0.32 b/s/Hz, MEG (cong )− 3.0 dB, and MEG-Ratio of (cong ) 0.0 dB. The SAR values also correspond to 0.6825 W/kg at 28.0 GHz and 0.3357 W/Kg at 38.0 GHz suggesting the features of the proposed work are suitable for future millimeter-wave applications.

The optoelectronic properties of ZnS doped with transition metals (Cu, Cd, Ag, and Au) are systematically investigated by applying first-principles computations based on the density functional theory (DFT). Various doping concentrations for Cu (5%, 10%, 20%), Cd (5%, 10%, 15%, 20%), Ag (5%, 15%), and Au (5%, 15%, 20%) are explored to examine their impact on the properties of ZnS. Our analysis confirms that all doped structures exhibit direct band gap semiconducting behavior. Notably, the band gap energy decreases with the incorporation of Cd, Ag, and Au, while an increase in Cu content results in a wider band gap. This work also evaluates how these transition metals influence the absorption coefficient, the dielectric constant, the refractive index, and the extinction coefficient of ZnS, providing a comprehensive insight into their effects. Our findings show a good agreement with existing experimental and theoretical data, offering a deep understanding of the optoelectronic properties of doped ZnS semiconductors. This investigation underlines the significance of doping in tailoring the properties of ZnS for enhanced optoelectronic applications, laying the groundwork for further experimental validation and theoretical analysis.