Chiral and Quantum Plasmonic Sensors: New Frontiers in Selective and Ultra-Sensitive Sensing

Surface Plasmon Polaritons (SPPs) and Localized Surface Plasmon Resonances (LSPRs) are fundamental phenomena in plasmonics that enable the confinement of electromagnetic waves beyond the diffraction limit. This confinement results in a significant enhancement of the electric field, making this phenomenon particularly beneficial for sensitive detection applications. However, conventional plasmonic sensors face several challenges, notably their difficulty in distinguishing chiral molecules, which are vital in drug development. Furthermore, these sensors exhibit sensitivity issues and energy losses, leading to broader resonance peaks and diminished signal-to-noise ratios. Recent research has concentrated on integrating chirality and quantum effects in plasmonics to overcome these limitations. Particularly, the development of plasmonic sensors with exceptional sensitivity and precision at scales smaller than the diffraction limit. This review assesses the latest advancements in chiral and quantum plasmonic sensing technologies. The first section details the theory and operational principles of conventional sensors based on SPPs and LSPRs. The second section discusses recent developments in chiral plasmonic sensors, while the third section focuses on plasmonic quantum sensing, highlighting contemporary findings. Specifically, this section emphasizes quantum-enhanced sensing techniques that mitigate shot noise, a significant barrier to single-molecule detection. The concluding section summarizes the review and identifies potential future research directions.