Fiber-optic membrane fluorescent sensor based on photonic crystal fiber with a glass rod in the fiber end

With multimode photonic crystal fibers (PCFs) serving as receiving fibers, a fiber-optic probe for the enhancement of fluorescence signal level is investigated. By sealing cladding air holes at the front end of the PCF, a segment of pure glass rod is formed. We prove that the PCF with a longer glass rod has a higher light collection capability. An initial theoretical model is presented to simulate the probe with a tilted target flat membrane placed in front of the probe end face at an arbitrary distance.