Nematic liquid crystal filled D-shaped voltage sensor with enhanced performance for power monitoring and fault detection in extreme environments.

A nematic liquid crystal voltage sensor with enhanced performance is proposed in this paper. The sensor is designed D-shaped using a single NLC filled core without the presence of air holes, which has made the sensor fabrication much simpler than previous sensors. The sensor also consists of a circular slot that provides a vast space for the surface plasmon resonance (SPR) phenomenon with a minimum amount of gold. The performance of the proposed sensor is carried out using a finite element method (FEM) based simulation. Following this, the sensor obtains a maximum wavelength sensitivity of 10 nm/V for a wide range of 190 V to 250 V with 5 V increments. The sensor also has a linearity of 0.9926 and a figure of merit (FOM) of 0.2V -1. It has a resolution of 0.01 V. The proposed sensor is a promising technology with a wide range of extreme and sophisticated applications. The sensor's simple structure, high sensitivity, resolution, linearity, and FOM make it perfectly suitable for a variety of sensing applications, including power monitoring, fault detection, medical diagnosis, voltage lines, electronics, etc.

High index core flat fiber surface plasmon resonance bio-sensor.

Due to tremendous design flexibility and ease of light control capability, the photonic crystal fiber offers efficient, flexible, and miniaturized plasmonic biosensors with attractive features. In this work, a high index (GeO2 doped silica) core flat fiber is proposed and analyzed for RI sensing ranging from 1.53 to 1.60. A rectangular analyte channel is created on top of a flat fiber to better handle the liquid analyte. To introduce the plasmonic effect, TiO2 and gold are deposited to the analyte channel. The sensing performance is carried out for two operating wavelengths, as two peaks are obtained for each analyte. The second operating wavelength shows better sensing performance than the first one. However, the proposed sensor offers average wavelength sensitivity of 5000 nm/RIU with a sensor resolution of 2×10-05 RIU. In addition, the proposed sensor shows identical linearity, which is quite rare in prior sensors. Moreover, the proposed flat sensor provides outstanding detection accuracy of 0.01nm-1, detection limit of 79.28 nm, signal to noise ratio of -4.1497dB, and figure of merit of 50RIU-1. Owing to outstanding sensing performance and a unique detection range, this sensor can be effectively used in biological and organic analyte sensing applications.

Designing of Hollow Core Grapefruit Fiber Using Cyclo Olefin Polymer for the Detection of Fuel Adulteration in Terahertz Region.

A grapefruit-shape hollow-core liquid infiltrated photonic crystal fiber (LI-PCF) is proposed and evaluated to identify the percentage of kerosene in adulterated petrol. The proposed hollow-fiber sensor is designed with Cyclo Olefin Polymer (Zeonex) and likely to be filled with different samples of petrol which is adulated by the kerosene up to 100%. Considering the electromagnetic radiation in THz band, the sensing properties are thoroughly investigated by adopting finite element method (FEM) based COMSOL Multiphysics software. However, the proposed sensor offers a very high relative sensitivity (RS) of 97.27% and confinement loss (CL) less than 10-10 dB/m, and total loss under 0.07 dB/cm, at 2 THz operating frequency. Besides that, the sensor also possesses a low effective material loss (EML), high numerical aperture (NA), and large Marcuse spot size (MSS). The sensor structure is fabrication feasible through existing fabrication methodologies consequently making this petrol adulteration sensor a propitious aspirant for real-life applications of petrol adulteration measurements in commercial and industrial sensing.

Slotted photonic crystal fiber-based plasmonic biosensor.

An optical fiber having the properties of photonic crystal and offering new diversity and features beyond a conventional optical fiber is the photonic crystal fiber (PCF). In this paper, a simplified version of a highly sensitive plasmonic sensor, called a "slotted PCF based plasmonic biosensor," is studied numerically with asymmetric air holes using the finite element method. From numerical records through the interrogation method, the maximum obtained wavelength sensitivity and amplitude sensitivity are 22000 nm/RIU and 1782.56RIU-1, respectively, with a maximum wavelength resolution of 4.54×10-6RIU-1 RIU for the y-polarized mode. Finally, optimization of the sensor performance is scrutinized, and the effect of different parameters is studied with proper resonance wavelength curve fitting. The design structure of the fiber is simple, symmetrical, easy to fabricate, and cost effective and has higher sensitivity than other PCF based sensors. Having a symmetric orientation of air holes, classic geometric structure, and higher sensitivity, it has the capability to be used in sensing applications, refractive index detection, and identification of biochemicals, biomolecules, and other analytes.

Negative curvature hollow-core anti-resonant fiber for terahertz sensing.

Hollow-core fibers are advantageous for chemical sensing as they facilitate liquid infiltration into the core over conventional porous core fiber. In addition, the requirement of less bulk material significantly decreases the effective material loss (EML). In this paper, a six circular cladding tube negative curvature hollow-core fiber (NC-HCF) is proposed for chemical sensing. Five different chemicals including chloroform, polylactic acid, CCL3, glycerin, and benzene are proposed to fill the core of the NC-HCF, and sensitivities are evaluated by full vector finite element method-based COMSOL software. Numerical results reveal that the proposed sensor exhibits very high relative sensitivity in a wide range of frequency. The fabrication of the proposed fiber is feasible by existing fabrication facilities as it contains realistic fabrication parameters. Hence, the proposed sensor can potentially be used as a chemical sensor especially in the medical, food, and industrial sectors as the five chemicals mentioned above carry great medical and food significance.