Analysis of one-dimensional photonic crystal based sensor for detection of blood plasma and cancer cells

We theoretically investigate the sensing performance of one-dimensional photonic crystal (PC) based sensor for the detection of blood plasma and cancer cells. The sensor consists of a sample layer sandwiched between two identical PCs of silica (SiO2) and titania (TiO2). The performance of the sensor is evaluated by using the transfer matrix method. We show a sensitivity of 71.25 nm/RIU while using the sample thickness of 100 nm, which can be increased to 161 nm/RIU by increasing the sample thickness to 300 nm. This however, requires a substantial quantity of the sample. We show that by using the additional layers of SiO2 on both the PC stacks the requirement of sample quantity can be reduced significantly while maintaining the same value of sensitivity. We show that using an additional layer of SiO2 can reduce the sample thickness by 14% while maintaining the value of sensitivity at 71.25 nm/RIU. The sensitivities of the proposed sensor for cancer cells and hemoglobin in blood plasma are more than 73 nm/RIU and 72 nm/RIU, respectively. The proposed structure is compact in size, easy to fabricate and cost effective.