Authors: Z-C Bai, S-J Qin, X. Zhang
Affilation: Guizhou University, China
Pages: 221 - 224
Keywords: fiber optic biosensors, micro channels, laser processing, tapered angle
With the development of micromachining technology, smart micro sensors have been a very potential technology. Micro channels products fabricated by micromachining technology have been put into markets in last years, such as inkjet tube of printer etc. Laser micromachining technology has a lot of unique advantages. High power Laser can be applied for processing 3D structural samples and high hardness materials which is not processed easily by IC technology. A novel fiber optic sensor based micro channels is introduced in this paper. Micro channels are processed by Nd:YAG Laser (wavelength 1.06μm) in surface of PMMA. The range from 300μm the end of the multimode optic fibers is etched cone surface by Chemical etching methods and cleaned by deionized water (Figure 1). The tapered angle is depended on chemical etching time. One multimode fiber is etched cone surface by chemical etching technology, which is engraved scraggly cone surface by high power Laser (wavelength 1.06μm) and cleaned by deionized water. Next, sodium dodecyl benzene sulfonate is used for washing it. The other multimode fiber etched cone surface by chemical etching technology is washed by deionized water. The multimode fiber of scraggly cone surface is fixed in one end of micro channels. The multimode fiber of cone surface is fixed in another end. The centre of the two fibers is aimed in micro channels. Cover glass is coved on micro channels. Fiber optic biosensors are made with above methods (Figure 2). Detecting system is shown in Figure 3. The function relation between the tapered angle and minimal receiving fluorescence angle of receiving fiber is obtained, which is . Where - refractive index for optic fiber core relative to detecting solution; -refractive index for optic fiber core relative to cladding, -optic fiber tapered angle, -minimum fluorescent incident angle. Glucose molecules solution marked with ZnSe nano crystal cluster is used as testing and verifying feasibility of fiber optic sensors. The intensity difference of the exciting light and receiving fluorescence of optic fiber is depended on the tapered angle of optic fiber. Fluorescence excited by the fiber of scraggly cone surface is not received completely by the fiber of cone surface (Figure 4). Adjusting the tapered angle suitably can increase receiving fluorescent intensity. When solution concentration is changed, the results are analyzed in micro channels which the diameter is 80μm.