The combined approach of optical fiber interferometry with molecular imprinting technology has shown a tremendous potential for developing a specific and sophisticated bio‐detection system with high degree of resolution and sensitivity. However, the specificity limitation of the fiber optic sensors renders them unsuitable for several key applications. Molecular imprinted polymer (MIP), an indispensable artificial molecular receptor with a complementary structure and functionality for the target analyte, possesses the ability to overcome the limitations of specificity. Therefore, a new class of artificial receptor‐based optical sensors (AROS) constructed from an optical fiber interferometer integrated with artificial MIP for selective and ultrasensitive sensing of urea is demonstrated. The sensor device shows an unprecedented sensitivity of 0.584 × 1011 nm m −1 and a lower detection limit of 17.1 fM with a wide dynamic range of 10−11–10−4 m. This demonstration of an ultrasensitive, selective, and accurate AROS system is bound to find potential applications that requires remote sensing in harsh environmental conditions with large fluctuations in the temperature, pressure, and humidity.

No abstract

Here, we report a photonic spin Hall effect (PSHE), i.e., splitting of opposite spin in a transverse direction using a multi-layered metallo-dielectric heterostructure by hybridization of a Tamm plasmon polariton and a surface plasmon polariton. The underlying mechanism of PSHE is also explained using the concept of superposition of normal and abnormal modes in the circular-polarization basis. It is revealed that the spin-dependent transverse shift for the proposed hybrid structure is enormously high owing to the transverse shift of ∼18  μm . The PSHE is found to be strongly dependent on the number of bi-layers of the structure and the analyte refractive index, which provides an additional degree of freedom for tailoring the device performance. Therefore, this study opens a pathway for developing next-generation photonic spin Hall devices in the fields of spin photonics, optical sensing, and optical communications.

Selective detection of toxic pollutants present in water has been a severe challenge to the scientific community for a long time. The noble integration of optical fiber-based interferometry with a bio-recognizing element molecular imprinting polymer (MIP) exhibits a promising technique for selective and susceptible biochemical detection. Here, we report a compact, stable, reproducible, and label-free optical sensor using a combined approach of photonic crystal fiber (PCF)-based modal interferometry and MIP nanoparticles (MIP-NPs) for selective detection of water pollutant p-cresol with an extremely low limit of detection (LOD). The MIP-NPs having a greater surface-to-volume aspect ratio allows more target analytes to bind. The sensor immobilized with MIP-NPs shows unprecedented sensitivity of 1.865 × 108 nm/M with specific and repeatable detection performance for a broad dynamic detection range of 10–8–10–3 M. The sensor offers a remarkable detection ability of as low as 1.55 nM concentrations of p-cresol in the aqueous medium, for water quality monitoring. Fast response, high resolution, compact size, label-free broad detection range, and selective reusable performance of the proposed sensor exhibit potential for board practical utilizations, including medical sectors, online and remote biosensing, and water resource monitoring.

No abstract