Research

This article introduces a research idea aimed at mitigating cross-contamination in biosensors. Recognizing the limitations of using a single-path sensor for detecting multiple analytes, we proposed a novel approach involving a sensor with multiple sensing paths and slots utilizing demultiplexer configuration. Each sensing slot is designated for specific samples and applications, thereby minimizing cross-contamination. By designing a sensor with multiple ports, it becomes feasible to detect numerous analytes efficiently. For instance, a dedicated port and slot approach improves accuracy and durability in scenarios like using plasma for glucose concentration detection and RBC for blood group detection. 

DOI: 10.1109/JSEN.2024.3372692

This article introduces a plasmonic magnetic field sensor (MFS) with a Metal-Insulator-Metal (MIM) waveguide and a W-shaped cavity filled with magnetic fluid. Operating on surface plasmon polaritons and magneto-optical properties, the MFS detects magnetic field strength by inducing a resonant wavelength shift. Numerical calculations demonstrate high performance, making this compact and cost-effective innovation a potential game-changer in navigation, medical diagnostics, and robotics, seamlessly integrating optical sensing into traditional devices and contributing to advancements in magnetic field sensing across various domains.

This article introduces a novel plasmonic refractive index sensor using a ZrN-Insulator-ZrN configuration, employing Zirconium Nitride (ZrN) with CMOS compatibility and tunable optical properties. The integration of ZrN provides advantages such as higher hardness, thermal stability, corrosion resistance, and lower electrical resistivity compared to traditional noble metals like silver and gold. The proposed sensor model surpasses conventional Metal-Insulator-Metal (MIM) arrangements, offering potential for highly efficient, robust, and durable nanometric sensing devices, bridging the gap between nanoelectronics and plasmonics. 

Most vital applications of the refractive index sensors are in biomedical applications like cancer cell detection, detection of blood groups, glucose and hemoglobin concentration in the blood, health care applications, detection of different viruses, and many other disease detections. In most of the cases of the biological specimen, the refractive index is found to be between 1.33 to 1.40. We work to design refractive index sensors that can detect different bio-cells as well as are compact in design with high sensing features for lab-on-chip applications.

Plasmonic devices are based on the propagation of surface plasmon polaritons (SPPs). SPPs are formed due to the interaction of electromagnetic fields and electron oscillations, which traverse on the interface between a conductor and a dielectric. The Refractive index sensor is one of the essential devices among the plasmonic devices for its application to detect the refractive indices of different dielectric materials present in the design of the sensor. The dielectric materials include a wide range of materials like gaseous materials, biomolecules, chemicals, etc. Our research focuses on the improvement of the key features of the RI sensors which ascertain the quality of the sensors by designing different topologies in a compact area.

The plasmonic devices formed with gold and silver have a number of limitations in dealing with optical losses, nanofabrication, tenability, chemical stability, and compatibility with conventional manufacturing processes. A number of alternative materials are suitable for overcoming these limitations through proper material engineering. These alternative materials not only are capable overcoming the limitations but also critical in device performance enhancement. In our research, we are exploring the prospects of replacing gold and silver with proper alternatives and designing plasmonic devices with them. These devices are capable of playing a crucial role to form a bridge between the conventional nanoelectronics and plasmonics.

An SPP-based pressure sensor is an optical device that intercepts applied pressure and translates it into optical signals. Optical pressure sensors have the advantage of being impervious to electromagnetic interference, have high sensitivity, signal transmission flexibility, and inexpensive manufacturing costs. In recent times, optical pressure sensing devices have been designed in a variety of ways to facilitate different lab-on-a-chip activities. However, the available pressure sensors lack the high sensitivity needed for diverse mechanical, electrical, and biomedical applications. In this project, we aim to pursue highly-sensitive plasmonic pressure sensors through novel techniques and surpass the existing state-of-the-art sensors.

With the variations of temperature, the optical properties of different materials changes. Capitalizing this characteristic change temperature of different media can be detected. For example, with the variations, a temperature, refractive index of different media such as alcohol, Polydimethylsiloxane, chloroform, toluene, etc. changes linearly. Hence, employing strong-light matter interactions of the plasmonic sensor the variations of refractive index so as the temperature can be detected in the lab-on-chip devices.

Metal-Dielectric-Metal (MDM) waveguide has the ability to support subwavelength wave propagation along with the metal-dielectric interface. Moreover, MDM waveguide facilitates the miniaturization of the plasmonic device confining light into the nanoscale region. However, owing to the longer penetration depth in the metallic region MDM waveguide suffers from metallic loss resulting in a smaller propagation length. On the other hand, a dielectric waveguide allows more propagation length though it doesn’t support nanoscale confinement. As a result, researchers have extensively studied the efficient coupling method between the dielectric waveguide and plasmonic waveguide in the same chip, where the former will be used as a medium of signal transportation and the latter will be used to address the subwavelength scale issue.