We report the emergent optical near field profiles from standard single mode optical fibers on the cleaved end of which were deposited particle-layers of SnO2. The layers, composed of micron and sub-micron sized particles, were deposited by means of the simple and low cost Electrostatic Spray Pyrolysis (ESP) technique. Powerful analytical tools such as Atomic Force Microscopy (AFM) and Scanning Near-field Optical Microscopy (SNOM) were used to obtain simultaneously the topography of the SnO2 layers and the related distribution of the intensity of the optical near field when the fiber-substrate is illuminated by a light radiation in the NIR range. We show that isolated microstructures, positioned in correspondence of the fiber core, reveal highly unusual capability of locally enhancing the optical near field. The observed phenomenon could lead to new concepts of fiber optic chemical sensors and in fiber microsystems as well.
© 2006 Institute of Electronics, Information and Communication EngineersPDF Article