Design of a Two-channel Photonic Crystal sensor for Explosive Detection

Use of explosives by terrorist organizations has increased extensively in recent years. It is important to develop non-destructive and highly sensitive sensors to detect explosives. In this paper, a Photonic Crystal sensor using waveguides and nano cavities in a hexagonal network of silicon rods in the air substrate is proposed. Nano cavities are filled by an organic material with refractive index of 1.59. This two-dimensional Photonic Crystal sensor can detect two different explosives, RDX and HMX, simultaneously. The area of this symmetrical hexagonal structure is 19×17µm2. The FDTD method with plane wave propagation was used for analysis. Simulation is performed and the transmission spectrum of the structure is plotted. The entry of explosive in to the sensor causes the change of the refractive index. The maximum amplitude of the transmission spectrum at the output of two channels at 1590 nm has been increased due to the difference in the light absorption. Then, a difference of 0.03 in the maximum amplitude of the transmission spectrum is shown because of two different explosives. This feature is very useful for sensing and detection applications. Quality factor (Q factor ) for the designed sensor has been measured bout 122.28.