Hybridization of surface plasmons and photonic crystal resonators for high-sensitivity and high-resolution sensing applications

Ultra-high-sensitive plasmonic sensor based on asymmetric hexagonal nano-ring resonator for cancer detection

A highly sensitive sensor based on two metal-insulator-metal waveguides coupled to an asymmetric hexagonal nano-ring resonator detecting cancerous cells is proposed. This novel design is utilized to facilitate the sensing of human cells. The sensing mechanism of the presented optical structure can act as a refractive index measurement in biological, chemical, biomedical diagnosis, and bacteria detection, which leads to achieving high sensitivity in the structure. The main goal is to achieve the highest sensitivity concerning the optimum design. As a result, the sensitivity of the designed topology reaches a maximum value of about 1800 nm/RIU (nm/refractive index unit) by controlling the angle of the resonator. It is evident that the sensitivity parameter is improved, and the reason for the increase in sensitivity is due to the asymmetry of the resonator, which has an 81 % increase in sensitivity compared to the symmetrical resonator, especially for blood cancer cells. The maximum quality factor obtains 131.65 with a FOM of 90.4 (RIU-1). The sensing performance of this proposed structure is numerically investigated using the finite difference time domain (FDTD) method with the perfectly matched layer (PML). Accordingly, the suggested high sensitivity sensor makes this structure a promising therapeutic candidate for sensing applications that can be used in on-chip optical devices to produce highly complex integrated circuits.

Numerical analysis of a highly sensitive SOI MRR refractive index sensor with performance enhancement using graphene and gold

This study proposes a simulation-based design for a Silicon-On-Insulator (SOI) ring resonator with a Figure of Merit (FOM) of 56.15 and a high sensitivity of up to 730 nm/RIU. The Finite-Difference Time-Domain (FDTD) technique was used to assess and evaluate the design quantitatively. Our design demonstrates higher sensitivity compared to many recent studies conducted on SOI-based sensors. The device structure follows a conventional ring resonator arrangement with a single waveguide, incorporating a 2D graphene layer on top of the SiO2 wafer and a gold nano-disc positioned at the center of the ring. Our findings highlight the device's susceptibility to refractive index variations, making it a desirable choice for various sensing applications. We have investigated the sensor's capabilities for sensing different concentrations of milkmilk. Graphene and gold materials enhance the device's response to light and provide comparatively higher sensitivity. The suggested design can serve as a blueprint for device fabrication, considering the practicality of implementing an SOI-based device using standard techniques for silicon processing.

A review on hybridization of plasmonic and photonic crystal biosensors for effective cancer cell diagnosis

Cancer causes one in six deaths worldwide, and 1.6 million cancer patients face annual out-of-pocket medical expenditures. In response to these, portable, label-free, highly sensitive, specific, and responsive optical biosensors are under development. Therefore, in this review, the recent advances, advantages, performance analysis, and current challenges associated with the fabrication of plasmonic biosensors, photonic crystals, and the hybridization of both for cancer diagnosis are assessed. The primary focus is on the development of biosensors that combine different shapes, sizes, and optical properties of metallic and dielectric nanoparticles with various coupling techniques. The latter part discusses the challenges and prospects of developing effective biosensors for early cancer diagnosis using dielectric and metallic nanoparticles. These data will help the audience advance research and development of next-generation plasmonic biosensors for effective cancer diagnosis.

A single-mode tunable plasmonic sensor based on an 8-shaped resonator for cancer cell detection

In this paper, a novel 8-shaped resonator coupled to metal-insulator-metal waveguides is used for designing plasmonic filters and sensors. The resonator supports two resonance modes, which result in peaks in the transmission spectrum of the structure. A Q-factor of 247.4 which can reach up to 270 at the wavelength of 1187.5 nm is observed. By placing vertical and horizontal metal blades in the resonator, two tunable single-mode plasmonic filters are obtained at the first and second resonance modes, respectively. The effect of structural parameters on the transmission spectrum is investigated using the finite-difference time-domain (FDTD) method. Based on the obtained results, the proposed plasmonic structure can be used for biosensing applications such as the detection of basal cancer cells with a sensitivity of 1200 nm/RIU. It is of great significance that both the sensitivity and Q-factor values for the proposed structure are higher than most recent sensors reported in the literature. Therefore, the proposed structure is a potentially promising candidate for filtering and sensing applications.