ABSTRACT
Near-eld scanning optical microscopy (NSOM/SNOM) is a microscopy technique for nanostructure investigation that breaks the far-eld resolution limit by exploiting the properties of evanescent waves with lateral resolution of 20 nm and vertical resolution of 2-5 nm that have been demonstrated. However, the current widely used NSOM probe by metal-coated tapered optical ber has intrinsic disadvantage of conning light in an inefcient manner due to its strong light propagation mode mismatch at the tip aperture. In this book chapter we propose a novel light-conning probe of the combination by the embedded metallic grating coupler and photonic crystal (PhC) slotted waveguide on
CONTENTS
7.1 Introduction ........................................................................................................................ 261 7.2 Design of Embedded Metal Focus Grating Coupler ..................................................... 263
7.2.1 Analysis of the Etched Dielectric Grating Coupler ...........................................264 7.2.2 Ag and Au Dispersion Optical Properties ......................................................... 267 7.2.3 Compact Embedded Metallic Focus Grating Coupler Overview ................... 269 7.2.4 2D FDTD Analysis of the Embedded Grating Coupler .................................... 270
7.3 Far-Field Radiation Pattern of the Embedded Metal Focus Grating Coupler ........... 271 7.3.1 Optical Antenna Theory ....................................................................................... 271 7.3.2 3D Directivity Analysis ......................................................................................... 272
7.4 Design of Slotted Photonic Crystal Nano-Resonator for Near-Field Light Focusing ........................................................................................276
7.5 Biological Applications ..................................................................................................... 279 7.5.1 Grating Coupler ..................................................................................................... 279
