Persistent organic pollutants (POPs) pose significant environmental and biological risks due to their stability and bioaccumulation in the food chain, often facilitated by contamination from sewage water. Monitoring POPs is crucial for assessing their detrimental environmental impacts and preventing related health issues. Conventional analytical techniques for detecting POPs typically require labeling, energy-intensive, and cost-effective equipment, can be time-consuming, and may alter the properties of analytes. In this study, we demonstrate a label-free biosensing approach utilizing spoof surface plasmon polaritons (SSPP) for the rapid and sensitive detection of commonly encountered POPs (including textile and paper dyes, worn-out antibiotics, and herbicides) in sewage water. Inspired by plasmonic, our results show that SSPP biosensors exhibit excellent sensitivity and selectivity for POPs in sewage water samples as small as 0.634 mL. Additionally, we validate the performance of our biosensors using real-time sewage water samples spiked with widely prevalent and harmful POPs, showcasing their practical utility in complex environmental matrices. This study underscores the potential of SSPP-based biosensing as a powerful tool for the label-free detection of POPs in sewage water, offering a rapid, sensitive, and cost-effective solution for monitoring environmental pollutants. Our findings contribute to water quality assessment efforts and the development of effective pollution mitigation strategies.

A Spoof surface plasmon polariton (SSPP) sensor is developed to identify honey samples by adding different concentrations levels of sugar (glucose and fructose). The SSPP-based sensor is integrated with a microfluidic reservoir to discriminate honey samples. The change in the resonating frequency shift with changed percentages of fructose and glucose levels of honey samples shows the performance of the SSPP sensor. This innovative approach presents a non-destructive, non-intrusive, label-free, rapid, and real-time methodology for analysing honey samples. The sensor exhibits exceptional sensitivity in detecting subtle differences in the dielectric constants of diverse samples. We systematically investigate the impact of distinct geometrical parameters on the sensor’s performance, focusing on optimizing its characteristics. A distinctive pentagon-shaped unit cell (UC) for the SSPP construction is thoroughly explored, revealing its unique performance and sensing capabilities. We construct a multilayer SSPP microwave structure with a pentagon unit cell to create a functional sensing platform for honey samples. The transient solver is used for computational analysis. Our results indicate a remarkable sensitivity of 1522 MHz/epsilon unit, with a correlation coefficient (R2) of 0.9367, for discerning between different dielectric samples ranging from 1 to 5 for normal pentagon unit cells. Additionally, for vertex-based pentagon unit cells, the sensor demonstrates a sensitivity of 1105 MHz/epsilon unit, with an R2 of 0.9524, when applied dielectric constants within the range of 1 to 5. These simulation outcomes highlight the viability of the suggested SSPP-inspired sensor as a promising solution for monitoring applied dielectric quality and characterizing the honey sample’s dielectric constants. This integrated approach showcases the potential to revolutionize quality assessment within the realm of honey production and diverse materials through its advanced sensing capabilities

It is important in the rising demands to have efficient anomaly detection in camera surveillance systems for improving public safety in a complex environment. Most of the available methods usually fail to capture the long-term temporal dependencies and spatial correlations, especially in dynamic multi-camera settings. Also, many traditional methods rely heavily on large labeled datasets, generalizing poorly when encountering unseen anomalies in the process. We introduce a new framework to address such challenges by incorporating state-of-the-art deep learning models that improve temporal and spatial context modeling. We combine RNNs with GATs to model long-term dependencies across cameras effectively distributed over space. The Transformer-Augmented RNN allows for a better way than standard RNNs through self-attention mechanisms to improve robust temporal modeling. We employ a Multimodal Variational Autoencoder-MVAE that fuses video, audio, and motion sensor information in a manner resistant to noise and missing samples. To address the challenge of having a few labeled anomalies, we apply the Prototypical Networks to perform few-shot learning and enable generalization based on a few examples. Then, a Spatiotemporal Autoencoder is adopted to realize unsupervised anomaly detection by learning normal behavior patterns and deviations from them as anomalies. The methods proposed here yield significant improvements of about 10% to 15% in precision, recall, and F1-scores over traditional models. Further, the generalization capability of the framework to unseen anomalies, up to a gain of +20% on novel event detection, represents a major advancement for real-world surveillance systems

The studies concerning solar cell technology has consistently been captivating and inspiring, largely because of its environmentally friendly and sustainable characteristics. The outstanding electronic, optical, mechanical, and electrical characteristics of perovskite materials make them crucial for the development of the photovoltaic industry. In order to model the mixed cation Rb0.05Cs0.1FA0.85PbI3 perovskite solar cells, the SCAPS-1D tool was used. The main feature of RbCsFAPbI3 perovskite is its remarkable stability, and wide bandgap. Rubidium (Rb) and cesium (Cs) cations improve the optoelectronic characteristics of the material, resulting in less non-radiative recombination and improved charge transfer. In this work, the effects of different hole transport layers (CuSCN, CuSbS2,Cu2O) and back metal contacts (Ag, Fe, C-Cu, Au, Ni, Pt) on solar cell performance were investigated. The maximum efficiency of the solar cell has been achieved by studying various parameters like temperature, series resistance, shunt resistance, defect density, and absorber layer thickness. With FF = 84.12%, Jsc = 24.52 mA cm?2, Voc = 1.19 V, and the configuration of FTO/TiO2/RbCsFAPbI3/Cu2O/Au, the optimised device obtains a PCE of 24.64%. The impressive enhancements in performance parameters observed in the structure of the device make it highly suitable for applications in solar energy harvesting systems

This study presents the design and analysis of a 5-channel dense wavelength division multiplexing (DWDM) demultiplexer based on a photonic crystal (PC) hexagonal ring resonator (HRR). By varying the radius of a unique hole inside each HRR, the novel method enables exact wavelength control. The apparatus is ideal for applications using Erbium-Doped Fiber Amplifiers (EDFAs) and operates in the wavelength range of 1535 to 1539 nm. With a maximum channel crosstalk of ?15.39 dB and an average channel coupling efficiency of 72.4%, the study shows good signal separation performance. The Plane-Wave Expansion (PWE) approach is used to determine the device's photonic band gap (PBG), and the Finite-Difference time domain (FDTD) method is used to analyze the electromagnetic (EM) field. This research contributes to the advancement of integrated optical components, showcasing the potential of PC-based devices in enhancing the capacity and efficiency of optical communication systems

A novel narrowband dielectric-based spoof localized plasmon polariton (DSLPP) with plasmonic waveguide sensor has been developed for biosensing applications. This sensor exhibits a narrowband response with good sensitivity and high-quality factor, characterized by resonances at 6.1 GHz and 8.2 GHz. The designed plasmonic sensor consists of coplanar waveguide (CPW) and plasmonic waveguide with a sandwiched resonator (SR). With the integration of plasmon waveguide and SR, a fundamental mode with high quality factor and multiple higher order modes are observed from the transmission coefficient spectrum. The proposed sensor is versatile and can be employed for detecting various diseases, including cancer and malaria, as well as for analyzing edible oils and other chemicals. Key advantages of this sensor include its simple design, tunability, narrow sensitive bandwidth, and high sensitivity. Moreover, it achieves very high-quality factor (Q) values for band I it is 1105.86 and band II, 1177.69, good sensitivity for band I it is 58 MHz/?r and for band II it is 114 MHz/?r, with the linearity R2= 0.9786, 0.9873 respectively, making it an excellent candidate for precise and reliable detection in diverse biosensing and chemical sensing applications

This study investigates the use of spoof surface plasmon polaritons (SSPPs) as an effective feeding mechanism for antennas functioning within the extremely high-frequency (EHF) range. A novel method is proposed for feeding a dielectric rod antenna with SSPPs, featuring a simple design made from FR-4 material with a relative permittivity of 4.3. In contrast to traditional tapered dielectric rod antennas and their feeding configurations, this design shows promise for achieving a gain of up to 16.85 dBi with an antenna length of 7.6 ?0. By carefully optimizing the design, impedance matching and directional radiation characteristics were obtained at 7.3 GHz. Simulations were conducted using CST Microwave Studio to validate and evaluate the design’s performance. The enhanced gain, improved impedance bandwidth, and use of cost-effective materials such as FR-4 present a compelling case for adopting this design in future wireless communication technologies. Additionally, the remote sensing properties of the feeder can be utilized for concealed object detection, material characterization, and the analysis of the spectral properties of materials.

This work explores the potential of spoof surface plasmon polaritons (SSPPs) for effectively feeding high-frequency antennas operating in the extremely high-frequency (EHF) range. An innovative approach is introduced in this study to utilize SSPP to feed a dielectric rod antenna. The design incorporates a straightforward dielectric rod antenna fabricated using FR-4 material with a relative permittivity of 4.3. Compared to conventional tapered dielectric rod antennas and their corresponding feeding configurations, this design presents the potential benefit of achieving an improved gain of up to 16.85 dBi using a specific antenna length of 7.6?0. Through careful design optimization, we achieved impedance matching and directional radiation characteristics at a frequency of 7.3 GHz. To validate our design and assess its performance, we conducted simulations using the CST Microwave Studio. This study aims to demonstrate the effectiveness and practicality of the proposed dielectric rod antenna with an SSPP feed

Multiple-Input Multiple Output (MIMO) systems require Orthogonal Frequency Division Multiplexing (OFDM) for effectively operating in multipath communication. Channel estimation is utilized in channel conditions where time-varying features are needed. However, Inter-Symbol Interference (ISI) occurs in MIMO-OFDM due to multi-path propagation, leading to inaccurate channel impulse response estimation. In this research, Improved Wild Horse Optimization (IWHO) is proposed based on three strategies namely, Random Running Strategy (RRS), Dynamic Inertia Weight Strategy (DIWS), and Competition for Waterhole Mechanism (CWHM) for pilot insertion which helps to estimate the channel accurately. IWHO increases the exploitation behavior and optimizes the global solution using three strategies. The input signal is encoded and decoded using Space Time Block Coding (STBC) to transmit data over noisy channels. Quadrature Phase Shift Keying (QPSK) is performed for modulation and demodulation in MIMO-OFDM. The Additive White Gaussian Noise (AWGN) channel is employed to transmit signals from the transmitter to the receiver. When compared to the existing techniques, pilot-based interpolation method, Discrete Fourier Transform-Least Square-Wiener (DFT-LS-Wiener), and Binomial Distribution-based Grey Wolf Optimization (BDGWO), the IWHO achieves a lesser Bit Error Rate (BER) of 0.0025 with Eb/N0 (dB) being 15. © (2024), (Intelligent Network and Systems Society). All rights reserved.

A novel integrated optic microring resonator (MR) and MR based force sensor is reported. The microring’s and bus waveguide’s width, and coupling gap of MR are optimized using Finite-Difference-Time-Domain (FDTD) Method. This optimized MR provides large FSR and high Q-factor. The optimized IOMR is used as an optical sensing element in force sensor. MR is integrated into the micro cantilever beam (MCB) of the force sensors. The radius and thickness of MR are considered as 5 ?m radius and 220 nm respectively, and length, width and thickness of MCB is considered as 75 ?m, 15 ?m and 300 nm respectively. The working principle behind the sensor is principle of photo-elastic effect. The effective refractive index of the sensor changes when a force is applied to the sensing element, which leads to a resonant wavelength shift of MR output characteristics. A shift in resonant wavelength is detected as a function of the applied force. The Finite-Element Method is used to analyze the sensor’s stress, and the FDTD method is used to analyze MR’s field propagation. The optimized MR provides an FSR of 22.29 nm. The sensitivity of the force sensor is 5 pm per 1?N and Q-factor is 18,241. The sensor range is from 0 to 1 ?N. The optimized MR can be used for different sensing applications such as force, pressure, acceleration sensing, biosensing, etc.

We explore the concept of spoof surface plasmon polaritons (SSPPs) as a means to confine plasmons on the surface of a tiny metallic structure. We focus on introducing an efficient transition design that confines the SSPP wave along a corrugated metallic strip with metal acting as a ground material. To achieve this, a unique unit cell specifically designed for waveguiding purposes was analyzed. The dispersion characteristics of this design were presented, demonstrating its potential for SSPP waveguiding applications. By varying the groove height from h1 to h7 (ranging from 0.5 to 3.5 mm), the SSPP waveguide was developed and analyzed its spectral characteristics through corresponding S parameters. Furthermore, the effects of altering the corrugated groove width from 1 to 2 mm was investigated. This variation is shown to have a linear impact on the gain, with a maximum gain of 7.71 dBi observed.

Surface Enhanced Raman Scattering (SERS) is emerging as a potent analytical tool for the detection of various pollutants in complex environments due to its distinctive vibrational fingerprint ability and pronounced detection sensitivity. Precautious of adverse blue-green economies and ecological impacts, sustainable generation of SERS active substrates and analyte casting matrices are getting prioritized. Herein, gold nanoflowers (AuNFs) of ?75 ± 15 nm were initially biofabricated using an expended cell culture medium as a one-step synthesis cum stabilization strategy. Then the heavy architecture of multi-faceted AuNFs with deep pits and edges, that acted as hotspots for enhancing the localized electromagnetic fields, was utilized for the direct SERS detection of commonly used carcinogenic herbicides collected from agro-farms at nanomolar regimes with 0.44 ppm and 0.27 ppm for Glyphosate and amino methyl phosphonic acid, respectively. Such a low level detection is superior by 8.33% when compared to the reported values. Computational finite-difference time-domain (FDTD) simulations affirmed the enhanced SERS effect from the multi-faceted nanostructure of AuNFs with structural heterogeneities that provide numerous hotspots to amplify the localized electromagnetic field. More eminently, fish scale derived biotemplate through AuNF-analyte drop casting contributed to the exceptional intensities, attributed to the naturally grooved hierarchically porous hydrophilic lamellar structures contact angle of 73°. Overall, the adapted bioengineering of SERS substrate is safe, robust, affordable and reproducible, fostered by bioderived durable biomatrix offering potent sustainable SERS detection of various biomedically and environmentally relevant molecules.

This research work describes, a novel integrated optic serially coupled micro racetrack-ring resonator (SCRR) based pressure sensor. Racetrack-ring resonators of radius 5?m and 4?m are chosen to create the Vernier-effect. The resonators are optimized for large FSR and high Q-factor by Finite-Difference-Time-Domain (FDTD) Method. The resonators are coupled serially between input–output waveguides to design a SCRR. The SCRR is used as a sensing element and integrated on silicon diaphragm. The sensor follows the Photo-elastic effect principle. When the pressure is applied on sensing element, there is a change in the effective refractive-index of sensor and leads to a shift in the super resonant wavelength. The shift is proportional to an applied pressure. So, the change in applied pressure is observed as a resonant-wavelength shift. The stress analysis of sensor is examined by Finite-Element-Method, and the field propagation of SCRR is examined using the FDTD-method. This sensor provides, high sensitivity of 1.04 nm per 100 kPa and Q-factor of 14084. The sensor range is 0 to 300 kPa.

Elastic optical networks enhance the flexibility of bandwidth distribution and making it precise, enables optimal use of the spectrum. The routing and spectrum problem (RSA) in spectrum-sliced elastic optical networks is addressed by a unique technique of spectrum allocation that uses Gaussian distributions. The routing algorithms used include balanced load spectrum allocation and shortest path spectrum reuse. The results show that using a Gaussian distribution method to distribute spectrum provides less blocking probability. For a 6-node and 14-node NSFNET topology networks with static traffic demands, the blocking probability of the algorithm is studied. The blocking probability for the proposed distributions is obtained and compared with the gold-fit algorithm and first-fit, exact-fit algorithms. The proposed algorithm shows the least blocking probability of 0.0125 for 150 cumulative average demand when compared to other algorithms.

A novel photonic crystal based hexagonal ring resonator (HRR) based 5-channel DWDM demultiplexer, its design and analysis is reported. The wavelength controlling of each channel is achieved by fine tuning of radius of special hole of HRR. Each channel of DWDM demultiplexer is designed with a PC-HRR consists of a special hole, which is incorporated in between hexagonal contour and input waveguide. And the radius of the special hole of each HRR varies from 95 to 115 nm with a variation of 5 nm. These five different HRR are connected serially by input-waveguide, which is used to couple the light. The air-holes on a silicon slab configuration is used in the device design. The resolved wavelength of this filter is in 1535–1539 nm range, where Erbium-Doped-Amplifier can be used. An average channel coupling-efficiency is 72.4% and channel cross talk is -18.31 dB reported. Photonic band gap of the device is computed by Plane-Wave-Expansion method. EM field analysis of this device is carried out by Finite-Difference-Time-Domain method.

We introduce an innovative, extremely sensitive microwave sensor that is based on Spoof Surface Plasmon Polariton (SSPP) like propagation and has an integrated chamber for liquid samples. By examining the impacts of variations in geometrical parameters on sensor responses, sensor performance is optimized for the ultra-sensitive identification of tiny dielectric constant in liquid specimens. When the sensor is loaded with a different sample, the variation in the resonance frequency is subsequently acquired. The findings show that the sensor has a high sensitivity 1055 MHz/epsilon unit and good linearity R2 = 0.927. The proposed sensor is a strong contender for the identification of minute variations in the dielectric constant of various samples.

An 8-channel DWDM demultiplexer is proposed with multiple designs and numerical analysis. Photonic crystal ring resonators of airholes on a 220 nm thick silicon slab are used as wavelength selective elements. Demultiplexers of three different designs are considered and their characteristics are analyzed. For all the three designs, the resolved wavelengths are in the range of 1530–1540 nm, where Erbium Doped Fiber Amplifiers are applicable. For the optimized device, the average coupling efficiency, cross talk are found to be 70.4% and ? 16.76 dB, respectively. Maximum and minimum coupling efficiencies of 79% and 56% are achieved. Photonic bandgap computation is performed by using plane wave expansion method and spectral characteristics are obtained by applying 3D finite difference time domain method.

Design and analysis of spoof surface plasmon polariton waveguide is presented in this work. The novel structure exhibits an improved gain of 6.973dBi with an increment of 0.83dBi compared to the existing designs.

A novel DWDM device based on Silicon Photonic Crystal (PC) slab is proposed. Hexagonal ring resonators are used for channel dropping purpose. Channel dropping is achieved by fine tuning of lattice constant inside the ring resonators. The device is designed in such a way that the demultiplexed wavelengths are in C band of electromagnetic spectrum where EDFA is applicable. An average channel spacing of 0.8 nm is obtained and the maximum cross talk between the adjacent channels is found to be a fraction of 0.07 of the applied input intensity. The coupling efficiency of the input power to the channels is observed to be 60%. Approximate footprint of the device is found to be 475 µm.

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A micro/nanofabrication feasible compact photonic crystal (PC) ring-resonator-based channel drop filter has been designed and analyzed for operation in C and L bands of communication window. The four-channel demultiplexer consists of ring resonators of holes in two-dimensional PC slab. The proposed assembly design of dense wavelength division multiplexing setup is shown to achieve optimal quality factor, without altering the lattice parameters or resonator size or inclusion of scattering holes. Transmission characteristics are analyzed using the three-dimensional finite-difference time-domain simulation approach. The radiation loss of the ring resonator was minimized by forced cancelation of radiation fields by fine-Tuning the air holes inside the ring resonator. An average cross talk of-34 dB has been achieved between the adjacent channels maintaining an average quality factor of 5000. Demultiplexing is achieved by engineering only the air holes inside the ring, which makes it a simple and tolerant design from the fabrication perspective. Also, the device footprint of 500 ?m on silicon on insulator platform makes it easy to fabricate the device using e-beam lithography technique.