We reported two kinds of fiber sensor based on double cascaded single mode fiber corners, which has a high sensitivity for refractive index (RI) sensing. RI sensing was experimentally demonstrated with average sensitivity of 95.5nm/RI unit (RIU) in a RI range from 1.333 to 1.421 and the other is 235nm/RI unit (RIU) from 1.333 to 1.418, which are relatively high among the previously reported similar fiber sensors (e.g., it is about 10 times higher than that of the normal two or three-cascaded-taper based Mach–Zehnder interferometer). Besides, The proposed RI sensors were fabricated only by a fiber fusion splicer. So , the fiber sensor is quite easy to made.
Proc. SPIE. 9142, Selected Papers from Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics: Optical Imaging, Remote Sensing, and Laser-Matter Interaction 2013
KEYWORDS: Gold, Optical filters, Nanoparticles, Spectroscopy, Luminescence, Fluorescence spectroscopy, Computing systems, Chemical analysis, Spherical lenses, Signal detection
The fluorescence spectra of melamine-contained milk solution excited by the exciting light have been experimentally studied in this paper. The experiments show that the melamine-contained milk solution can produce strong fluorescence when excited by 467nm exciting light. The fluorescence spectrum peak is around 540nm and the fluorescence intensity would increase firstly and then decrease with the increasing concentration of melamine in pure milk. Based on this result, combining with the optical technology and computer technology, a simple detection system device has been designed. The device can quickly detect whether the milk containing melamine in real-time and accurately show the concentration of melamine in a certain range, which make the device have strong practicability.