Refractive index EV sensor based on conventional and mirror image 1D defective photonic crystal designs: theoretical study

In the present study, we have theoretically investigated the sensing and detection mechanism of refractive index of various samples containing extracellular vesicles by using the conventional and mirror image 1D defective photonic crystal designs. The transfer matrix method has been used to analyze the transmission properties of both structures at normal incidence. The performance of the proposed designs has been examined by measuring the shift in the position of the defect mode inside PBGs of respective structures depending upon the corresponding change in refractive index of various EV samples. The comparison between the observed data with the experimentally available standard data may be used to find out refractive index of unknown EV samples. Moreover, mirror image 1D defective PC design can be used as an alternative of one-dimensional annular photonic crystal without defect with air core in which propagation of electromagnetic waves is only along the radial direction. Finally, we have compared the sensing and detection features of both the designs made up of a conventional and mirror image 1D defective PCs. It has been noticed that the mirror image defective structure provides a narrow transmission peak of unit transmittance inside the PBG. This remarkable feature of mirror image one-dimensional defective photonic crystal design may be utilized to develop various highly sensitive sensors. The figure of merit and quality factor values of the proposed design are high and low, respectively. Such high performance bio-sensor with better sensing capabilities may be very useful in chemical and biological sample detection.