chapter  5
54 Pages

Modeling Optical Applications of Nanofibers/Nanowires

WithYipei Wang, Limin Tong

Surface Roughness ................................................................................................. 142 5.4.4 Dependence of Roughness-Induced Loss on the Diameters

of Nanobers ..................................................................................................... 143 5.4.5 Dependence of Roughness-Induced Loss on the Wavelength of Light ......... 144

5.5 Bending Losses ................................................................................................................... 144 5.5.1 Mathematical Model .............................................................................................. 145 5.5.2 Electric Field Energy Distribution ....................................................................... 146 5.5.3 Dependence of Bending Loss on the Bending Radii and Polarizations ........ 147 5.5.4 Dependence of Bending Loss on Wavelength of the Guided Light ............... 147 5.5.5 Dependence of Bending Loss on Diameter of the Nanowire .......................... 148 5.5.6 Dependence of Bending Loss on Refractive Index of the Nanowire ............. 149

5.6 End-Face Output Patterns of Nanowires/Nanobers .................................................. 149 5.6.1 Mathematical Model .............................................................................................. 149 5.6.2 Nanobers with Flat End Faces ........................................................................... 150 5.6.3 Nanobers with Spherical and Tapered End Faces .......................................... 151

5.7 End-Face Reectivities of Nanowires ............................................................................. 153 5.7.1 Mathematical Model .............................................................................................. 153 5.7.2 End-Face Reectivities of Freestanding Nanowires ......................................... 154 5.7.3 End-Face Reectivities of Nanowires with Substrates ..................................... 155

As typical 1D wire-type waveguides with diameter or width close to or below the wavelength of the light, optical nanobers/nanowires offer interesting properties including tight optical connement, high fractional evanescent waves, steep eld gradient, and abnormal dispersion, which open opportunities for developing nanophotonic components and devices ranging from lters, interferometers, resonators, and lasers to sensors.