Pitamber Mahanandia

This study explores the design and optimization of a planar plasmonic nano-slit array for scalable high-sensitivity refractive index sensing in the visible–near infrared (Vis-NIR) spectrum. This functionality arises from the excitation of surface plasmons (SPs) at the metal–dielectric interface, whose resonance position is acutely sensitive to minute variations in the refractive index (RI) of the adjacent medium. While many sensors report higher sensitivities, they often suffer from complex designs or multilayer architectures, which limit their practical viability and scalable production. Addressing this critical trade-off, the optimized geometry yields a high sensitivity of 458 nm/RIU, establishing an optimal balance between competitive performance and structural simplicity for scalable fabrication. Parametric analysis confirms that the sensitivity scales linearly with periodicity across the tested spectral range, while the figure of merit (FOM) is maximized at a periodicity of P =500nm, providing a clear design rule for efficient sensor fabrication.

This study presents an improved quantum teleportation protocol designed to enhance fidelity in noisy environments by combining weak measurements (WMs) with flip and reversal operations. In our scheme, Alice prepares a four-qubit entangled state and shares one of the entangled qubits with Bob, which serves as the quantum channel for teleporting an arbitrary single-qubit state. Since the communication channel is subject to noise, Alice performs a weak measurement on the shared qubit before transmission to reduce the impact of decoherence. Building upon existing WM-flip-reversal frameworks, we propose a modified weak measurement and reversal (WMR) protocol tailored for different noises in a four-qubit entangled system. The approach applies WM and flip operations prior to transmission to enhance resilience against noise, followed by corresponding reversal operations after transmission to recover the original quantum state. We systematically compare the performance of our proposed WMR protocol with the previously proposed WM-flip-reversal method under three common noise models: amplitude damping channel (ADC), phase flip channel (PFC), and bit flip channel (BFC). Our analysis reveals that the modified WMR scheme achieves significantly higher teleportation fidelity and improved robustness, particularly in bit flip noise environments. These findings highlight the potential of optimized weak measurement strategies for developing more reliable and noise-tolerant quantum communication protocols.