Explosives detection by fluorescence quenching of conjugated polymers in suspended core optical fibers

In this work we demonstrate a suspended core microstructured optical fiber-based sensor platform for explosives detection based on the fluorescence quenching of a surface-attached conjugated polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV). These fibers allow for strong evanescent field interactions with the surrounding media because of their small core size, and can sample minute liquid volumes. This is the first demonstration of a fluorescent conjugated polymer sensor capable of measuring liquid explosives samples loaded within an optical fiber. This technique is used to identify 1,4-dinitrobenzene (DNB), a member of the nitroaromatics family of explosives, in acetone for concentrations as low as 6.3 ppm in a total sampling volume of 27 nl and to quantify its concentration using the fluorescence decay lifetime, requiring an analysis time of only a few minutes.