RESUMEN
An all-fiber temperature sensor employing intentional refractive index modulation is experimentally demonstrated. The sensor consists of four sections of polarization maintaining fiber (FPMF) sandwiched between multi-mode fiber (MMF). The stress region of two sections of polarization maintaining fibers (PMFs) is aligned and then anti-clockwise rotates one PMF in 10 deg angles while the other keeps still. Finally, the discharge proceeds. The remaining two PMFs are fusion spliced with the same method. Then the prepared FPMF-MMF structure is connected to the 3 dB coupler to construct a Sagnac loop. The temperature sensitivity reaches 1.49 nm/°C for a temperature range from 16°C to 55°C. The proposed temperature sensor with easy fabrication and good linearity in measuring temperature can be a promising candidate for various applications in environmental monitoring and industrial production.
RESUMEN
Quartz crystal microbalance (QCM), surface acoustic wave (SAW)-Rayleigh and ZnO based SAW-Love sensors were fabricated and their sensitivity was comparatively analyzed for the quantification of Staphylococcus aureus (S. aureus). The SAW based sensors showed response magnitudes up to three times greater than that of the QCM sensor for the same mass loading of S. aureus. The ZnO nanoparticle-based SAW-Love sensor has a maximum mass loading sensitivity of 328.75 Hz ng-1. The SAW-Love sensor achieved a lower limit of detection of 2 × 103 CFU mL-1 compared to the QCM counterpart (2 × 105 to 2 × 106 CFU mL-1) under the same conditions. The SAW-Love sensor could be used as a disposable chip in micro or ultra-trace accurate diagnosis methods.
RESUMEN
The purpose of overviewing research and development status of dependable, efficient, and portable and miniaturized surface acoustic wave (SAW) is to propose practical devices for biosensing and medical diagnosis. SAW Love-mode sensors fortunately have a great deal of attention during last two decades. Several periodic structure models of SAW devices were reviewed, especially interdigital transducers (IDTs), wave guiding layers, patterned-ZnO. SAW devices based on such periodic wave guiding layers and patterned-ZnO were demonstrated with superior performance, much better than conventional SAW devices. Both 2D and 3D models of phononic-crystal-based SAW devices can be respectively fabricated by an array of periodic cylindrical holes and pillars, which allowed SAW devices to have both higher Q-factor and GHz-level frequency. Ring waveguide and spherical SAW devices would have potential applications and implementation in biosensing. ZnO is one of attractive guiding-layer materials. Its nanostructures, such as nanowires, nanorods and nanofibers provided with excellent properties, will make nanoscaled SAW devices contribute to be much more sensitive in biosensors. A range of applications based on SAW and ZnO guiding-layer would be therefore expected among of immunochemical analysis, in-situ virus or bacteria determination, microfluidic automation, and cell manipulation.
