Crossed grating sensing refractive index change in the non-laboratory environment

Surface plasmon polaritons (SPPs) have been widely applied to refractive index (RI) sensing for their extremely high sensitivity to the surrounding RI change. Many efforts have been devoted to narrowing the linewidth of the SPP mode and enhancing the sensitivity of SPP sensors. However, most reported SPP-based RI sensing platforms could only operate in a laboratory environment for their bulky volume or sophisticated measuring systems. In this context, we have developed a miniaturized and portable RI sensing platform based on a 2D crossed grating coupled SPP sensor that can work under a non-laboratory environment. The crossed grating is fabricated by the laser interference lithography (LIL) method, which is cost-effective and reproductive. A series of glucose solutions with different concentrations have been used as analytes to verify the sensing performance of the fabricated crossed grating.