An ultra-compact plasmonics-based sensor is investigated which is excited by Fano resonance. The structure is numerically simulated by the finite-difference time-domain method. The sensor utilizes unique waveguide geometry named as metal-insulator-metal (MIM) waveguide geometry which has an intriguing feature to confine signal far beyond diffraction light. Thus, it is used to devise ultra-compact optical circuits. The MIM waveguide is coupled to a pair of elliptical ring resonators and the interaction between the resonators excites special mode which is known as Fano resonance mode. It is a unique phenomenon which exhibits asymmetrical resonance profile and supports ultra narrow line width. Because of its exciting feature, a large value of sensitivity = 1100 nm/RIU and figure of merit = 224RIU ^-1 is obtained for the proposed sensor. The sensing performance of the device can be further enhanced by tailoring the geometrical parameters. The applicability of the device is also tested to detect the concentration of hemoglobin in blood. Thus, the device is well suited to design on-chip optical sensors.

In this work, a novel design of Zinc Oxide (ZnO) and bi-metallic (Ag–Au) layers based surface plasmon resonance (SPR) biosensor with barium titanate (BaTiO₃) and graphene is proposed. The proposed structure consists of SF10 glass prism, ZnO, Ag, Au, BaTiO₃, and graphene as a top layer for biomolecules adsorption. Here, the performance of this structure is studied and analysed for sensitivity along with the accuracy of detection and quality parameter for the shift in refractive index (RI) from 1.33 (sensing medium) to 1.45 and our reported results show that addition of bimetallic (Ag–Au) layers along with BaTiO₃, improve the sensitivity of the proposed structure to 14.85% for the same RI range compared to last reported MoS₂-graphene-based SPR sensor. Here at $\lambda =632.8\text{nm},$ maximum sensitivity is reported as 116.67 degree/RIU while the accuracy of detection and the quality parameter are obtained as 4.54 and 37.87 RIU⁻¹ respectively. These high-performance parameters of the design make this structure suitable for biosensing applications.

This work presents the design and simulation of an all-optical sensor for detection of cancer cells. The proposed device is based on the surface plasmon resonance effect on a spiral shaped photonic crystal fiber structure. The finite element method (FEM) based simulations are carried out for the different cancer cells, such as HELA, Basal, Jurkat, and MDA-MB-231, MCF7, and PC12 detection. The sensor has shown the maximum sensitivity of −289 RIU−1 for the refractive index of the detection of breast cancer cell with the resolution of 2.33 × 10−4. The sensor is effective for the refractive index range of 1.36 to 1.401.The structure is based on spiral shaped photonic crystal fiber, and has shown promising linear sensing response to support the practical feasibility of the device. The proposed sensor design is effective in detecting cervical cancer, skin cancer, blood cancer, breast cancer type 1, breast cancer type 2, and adrenal gland cancer.

The development of compact, highly sensitive sensors for real-time analyte detection is crucial for medical diagnostics. The promising characteristics of photonic crystal fibers (PCFs) have captivated researchers, driving efforts to develop sensors for early cancer detection. The microscopic air holes within the PCF structure allow analytes to be inserted, enabling precise interaction between confined light and analyte for detecting malignancies. This review examines PCFs’ potential in cancer detection, focusing on principles like evanescent waves (EWs), surface plasmon resonance (SPR), surface-enhanced Raman scattering (SERS), and interferometry. SPR-based PCF sensors stand out for their design flexibility and optical properties, showing great promise for cancer detection and potential clinical applications. This review also emphasizes recent developments in PCF-SPR sensors, addressing their performance and possible improvements.

This paper presents a systematic numerical investigation of a surface plasmon resonance (SPR) sensor based on photonic crystal fiber (PCF). The proposed design is modeled and simulated using the full vectorial finite-element (FV-FEM) technique and sensing characteristics such as confinement loss behaviors, phase matching and sensitivity are investigated and presented. The plasmonic layer is made up of TiO ₂ and gold for improved sensitivity. The reported sensor exhibits an amplitude sensitivity of -374.062 RIU ^-1 and a wavelength sensitivity of 2000 nm/RIU for the refractive index (R.I.) sensing range of (1.39-1.44), according to the loss spectrum shift. The reported hoop-cut photonic crystal fiber surface plasmon resonance sensor is suitable for biosensing and chemical sensing applications because of its broad range (1.39-1.44) of analyte detection.