Photonic crystal biosensor for refractive index based cancerous cell detection

A novel technique has been reported in the present research to sense the nature of different cells either normal or cancerous by employing a 2-D photonic crystal waveguid (PCW), where the suggested structure is realized through 5 × 5 silicon based rods etched on a square lattice having a central defect with air as the background. To envisage accurate sensing, we have focused on two groups of live cells, out of which one is normal cell group (INOK) and the other one is cancerous cell group (YD-10B). Plane wave expansion (PWE) method has been suitably manipulated to realize electric field distribution and peak reflected wavelength in the proposed PCW structure. Various structure parameters such as lattice spacing, diameter of circular rods and nature of the background material have engaged as crucial roles for the accomplishment of proper sensing of normal and cancer cells. The simulation outcomes asserted that for normal cells, reflected wavelengths fall in the orange color wavelength range whereas for cancerous cells, the reflected wavelengths lie in the yellow color wavelength range. Further, the detailed investigations on negative dispersion coefficient, scattering loss and nonlinear coefficient are carried out for the proposed structure by separately considering the normal cells and cancerous cells. Apart from this, a high sensitivity of 2360.12 nm/RIU, a very low resolution of 1.78 × 10−6 and high quality factor of 99.765 is achieved for the proposed sensor which claims the accuracy in sensing of normal cells and cancerous cells. Moreover, the aforementioned sensing principles open up a convenient and simple way to sense the cancer cells, which can find a suitable application as a biosensor in biophotonics.