Ultra-sensitive photonic crystal cancer cells sensor with a high-quality factor

In the present study, we develop a photonic biosensor based on a one-dimensional photonic crystal. Different types of cancer cell detection methods are developed by introducing a defect layer in the photonic crystal using cancer cells. The sensing mechanism of the present cancer sensor is based on varying the refractive index of the analyte, which leads to shift in the transmission or the reflection spectrum. By using the transfer matrix method, the s-polarized light (TE) is calculated, and a significant effect on the resonant defect peak is observed when the angle of the incident light or the defect layer thickness changes. In current work, the resonant defect peak at the optimum conditions is red-shifted from 1538 to 1648nm as the cancer cell layer refractive index changes from 1.350 to 1.401. Therefore, the proposed biosensor is designed with high sensitivity (S = 2200 nm/RIU) in the range of refractive index from 1.350 (zero cancer cell) to 1.401 (MCF-7 cancer cells). Thus the high Q (quality factor) is enhanced, which in turn makes the detector more sensitive for a slight change in the index.