A novel rhombic shaped photonic crystal bio-sensor for identifying disorders in the blood samples

In this work, a single and dual rhombic-shaped ring resonator (RR) bio-sensor using 2D photonic crystal (2D-PhC) are designed and simulated with circular Si rods in a square lattice in an air arrangement. The photonic band gap (PBG) of the structure is calculated using plane wave expansion (PWE) method. The simulation and investigation of the bio-sensor structure is carried out using finite-difference time-domain (FDTD) method. The optimized simulation parameters like rod radius, lattice constant, angle of incidence and cavity thickness are 142 nm, 630 nm, 90° and 2 μm respectively. A small change in refractive index (RI) will cause a considerable shift in the resonant wavelength and transmission output. The proposed bio-sensor is capable of analyzing eleven different components of blood based on the RI. Many blood-related disorders such as nutritional deficiency, inflammatory bowel disease (IBD), leukemia, lymphoma and thalassemia can be found using this bio-sensor in less time and with minimum human effort. The average quality factor (QF), sensitivity and transmission efficiency (η) of the bio-sensor are 3702, 166 (nm/RIU) and 80% respectively. This design is instigated for medical applications with a compactness of 515.29 μm².