Nanocavity-Coupled Waveguide Photonic Crystal Biosensor for Detection of Hemoglobin Concentration in Blood

Biosensor is an analytical device which is used to detect the biological analyte which can be antibodies, enzymes, cells, or biomolecules. The biosensor has many applications like in biomedical research, environmental monitoring, and healthcare. In this paper, we have designed a 2D photonic crystal biosensor with nanocavity coupled with a photonic crystal waveguide. This structure possessing hexagonal symmetry with an area of 19 x 13 mu m(2) is considered. Over the wafer of air, dielectric rods of Si which have refractive index of 3.47772, radius of 210 nm, and lattice constant of 700 nm are introduced. This design is based on hemoglobin-filled nanocavity coupled with a waveguide. The biosensor can detect hemoglobin concentration in blood. Hemoglobin concentration in blood with 0, 10, and 20 g/dL is detected through the simulation and analysis. For the analysis, FDTD method is used. Change in refractive index causes a spectral shift in transmission spectra is observed. This property is useful in sensing application by considering different concentration with different refractive indices. In this work, design is allowed to operate in the wavelength range of 1500-1600 nm.