Optical nano-textile sensors based on the incorporation of semiconducting and metallic nanoparticles into optical fibers
- PDF / 139,165 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 49 Downloads / 217 Views
0920-S05-06
Optical nano-textile sensors based on the incorporation of semiconducting and metallic nanoparticles into optical fibers Anuj Dhawan1, John F. Muth1, Dennis J. Kekas1, and Tushar K. Ghosh2 1 Electrical and Computer Engineering, NC State University, Raleigh, NC, 27695 2 College of Textiles, NC State University, Raleigh, NC, 27695 ABSTRACT By incorporating optical fiber based devices into woven and non-woven fabrics, one can distribute these devices across large areas. In this work, novel fiber optic devices with nanofunctionality are developed by incorporating metallic and semiconducting films and nanoparticles inside the optical fibers. This is accomplished by first depositing the material of interest on the tip of the optical fiber, then overcoating the fiber with a protective layer of silicon dioxide before fusing this structure to an optical fiber. This results in a continuous fiber that can be woven, or placed into nonwoven textiles. In this study the incorporation of gold nanoparticles and vanadium oxide compounds into the core of optical fibers and an in-line Fabry-Perot sensor using these techniques are described.
INTRODUCTION Devices based on optical fibers have several potential advantages over electronic sensors including the immunity to electromagnetic interference, not needing to be locally powered and the possibility of wavelength multiplexing. Development of fiber optic devices like strain, chemical, and temperature sensors has been reported in the literature [1-2]. Optical fibers also provide an excellent platform to exploit the wide range of functionality inherent in nanoparticles, like nonlinear saturation effects and high recombination efficiency and plasmon effects, at the macroscopic level. Recently we have been investigating novel fiber optic structures for in-line optical sensors [3-4] and temperature sensors [5] that use metallic & semiconducting thin films and nanoparticles as building blocks for developing optical fiber sensors and devices. Metallic nanoparticles are well known for plasmon resonance effects [5], which can be utilized for sensing purposes. In this paper gold was chosen as the material of choice for forming metallic nanoparticles since it is inert and its properties are well behaved. It was also found that gold films could be preserved during the process forming partially reflective mirrors suitable for a Fabry-Perot Cavity. Vanadium oxide films were also investigated for possible applications where the semiconductor to metallic phase changing properties could be exploited.
Figure 1. (a) Effect of plasma arcs on plasmon resonance of nano-particles on the tip of an optical fiber and (b) Effect of thermal annealing to form nanoparticles. EXPERIMENTAL AND RESULTS In order to incorporate the gold nanoparticles into the core of a silica optical fiber, a discontinuous thin gold film (4-8 nm thick) was deposited on the cleaved tip of a 62.5/125 µm step index multimode fiber by employing e-beam evaporation. An electron beam, having a 65-75 mA beam current, was directed
Data Loading...
