Evanescent Field Imaging of Novel Optical Waveguide Structures: An Ultra-HighSpatial Resolution Probe of Topographic, Dielectric, and Spectroscopic Properties

摘要

Under this grant we have carried out a research program utilizing near fieldoptical microscopy (NSOM) to investigate spatial configurations of both integrated photonic structures and semiconductor nanostructures. Near field techniques have become attractive for optical characterization because by probing the near field the diffraction limit of conventional microscopy can be overcome. Spatial resolutions much smaller that the optical wavelength (lambda) can be obtained, approaching lambda/50. In the grant we have custom-built an NSOM instrument and reported the first results on the use of near field techniques to measure and image (1) the transverse field across an optical channel waveguide, (2) the evolution of the transverse field variation as light propagates through the integrated optic structures of a directional coupler and a y-junction, and, (3) very recently, have accomplished the extension of these near field techniques to the study of field distributions in semiconductor waveguide structures where to model our experimental results the use of the beam propagation method is required.