1. Introduction to Surface Plasmon Resonance (SPR) Surface plasmon resonance (SPR) refers to the resonant, collective oscillation of free electrons at a metal–dielectric interface, driven by p-polarized electromagnetic excitation under conditions that enable coupling between incident light and surface-bound charge density waves. In the canonical sensor geometry, this coupling is achieved under total internal reflection, […]
Surface-Enhanced Raman Scattering (SERS) is a powerful technique that amplifies Raman signals of molecules adsorbed on nanostructured metallic surfaces. This enhancement enables the detection of trace levels of chemical and biological species, making SERS a cornerstone in modern analytical chemistry, biosensing, and nanophotonics. In this article, we dive into the principles, simulation methodologies, and future […]
Why this question matters now We open with the modern reality: most “high-performance” SPR sensors are no longer just prism/metal/analyte. Once you add oxides, high-index films, and 2D overlayers, sensitivity can improve dramatically—but so can linewidth, drift, and fabrication sensitivity. This section frames the goal of the article: to explain what actually controls sensitivity in […]
The Quiet Revolution in Plasmonic Sensing Surface Plasmon Resonance (SPR) has long stood at the forefront of optical sensing technologies—renowned for its label-free detection, real-time analysis, and ultra-sensitivity to minute changes in the refractive index (RI) of nearby media. In biological, chemical, and environmental diagnostics, SPR sensors provide a reliable window into molecular interactions, gas-phase […]
Surface plasmon resonance (SPR) refers to the resonant oscillation of conduction electrons at a metal–dielectric interface excited by incident electromagnetic radiation under specific momentum-matching conditions. Surface plasmon–based sensors exploit this phenomenon to detect minute changes in the refractive index near the sensor surface, enabling highly sensitive, label-free detection. Within the broader category of plasmonic sensing, […]
1. Introduction: The Digital Twin of Plasmonic Sensing Surface Plasmon Resonance (SPR) represents one of the most powerful and sensitive label-free detection techniques in modern photonics. Characterized by the resonant oscillation of free electrons at a metal-dielectric interface, SPR sensors have found widespread applications in biosensing, chemical detection, and environmental monitoring. However, their development traditionally […]
Photonic Crystal Fiber (PCF) sensors represent a class of advanced optical fiber technologies that are revolutionizing the landscape of precision sensing. Unlike conventional step-index optical fibers, PCFs incorporate a microstructured arrangement of air holes along their length, giving them unique light-guiding properties. These periodic structures allow PCFs to confine and guide light either through modified […]
Introduction Surface Plasmon Resonance (SPR) sensors stand at the forefront of label-free biosensing technologies, relying on the excitation of surface plasmons—coherent electron oscillations—at metal-dielectric interfaces. The resonance condition, and hence the sensor’s response, is acutely sensitive to changes in the local refractive index, making SPR particularly valuable in the detection of biomolecules, chemicals, and environmental […]
Introduction Photonic crystal fiber (PCF)-based gas cells (PCF Sensor) have emerged as an indispensable component in optical gas sensing, particularly in Raman and absorption-based techniques. These gas cells offer significant improvements over traditional sensing architectures by enhancing light-gas interaction length, enabling miniaturization, and offering higher sensitivity and selectivity. The structure of PCFs, characterized by microscopic […]
Introduction Zeta potential, often denoted as ζ-potential, is the electrokinetic potential that develops at the slipping plane of a particle in a liquid medium. It quantifies the electrical potential difference between the dispersion medium and the stationary layer of fluid attached to the dispersed particle. In simple terms, it measures the degree of electrostatic repulsion […]
