Lab-on-a-fiber device for trace vapor TNT explosive detection: Comprehensive performance evaluation

Based on the previously proposed concept of a lab on a fiber (LOF) and an LOF-based platform for detecting trace vapors of TNT explosives, in this paper, we study the compatibility of the LOF device with a preconcentration unit. We report the detail investigation of factors that crucially affect the overall performance of this LOF platform. From a theoretical perspective, we investigate the efficiency of a light source formed at the fiber tip on sensory film excitation. Experimentally, we demonstrate the much faster response time of the LOF over a sensory film on a bulky planar glass substrate. We also evaluate the following factors that significantly impact the sensitivity of the instrumentation system: 1) the proper bond between the sensory film and the fiber surface; 2) the concentration of polymer solution for thin-film formation; and 3) the degradation of thin film in the presence of ambient light and the oxygen content in the air.