A High Sensitive Formaldehyde Photonic Crystal Fiber Sensor Based on Lossy Mode Resonance

Along with the continuous expansion of the global food supply chain, the demand for portable detection of formaldehyde in water, especially formalin, is increasing. In this work, we present a new fiber sensor on the basis of lossy mode resonance (LMR) to detect Formalin.TiO2-ITO-TiO2 trilayer films have been coated onto the uncovered area of core of micro-structured fibers (MSF) as an interacting material. The exposed core LMR area brings about a significant amount of birefringence, which ultimately results in a peak separation in both the X and Y polarization orientations. We numerically analyze the effects of the core exposure area on the sensor performance. The stimulation results indicate that a sensitivity of 8558 nm/RIU, that means 9.4994 nm/1% for formaldehyde detection, is obtained. From this work, a conclusion can be drawn that the TiO2-ITO-TiO2 trilayer micro-structured fiber sensor based on LMR is pretty suitable for the detection of formaldehyde solution and other aqueous solutions, which will play an essential role in the manufacture of the LMR-based MSF sensor and the detection and prevention of formaldehyde.