Apertureless Scanning Near-Field Infrared Microscopy of Polymers

摘要

Infrared near field microscopy using an apertureless probe technique has been accomplished to study the surfaces of a cast copolymer film. Two basic models for the predicted signal and the experimental data are presented. The first model includes plane wave light scattering by a conductive sphere and an infinitely wide absorptive layer placed on a semi-infinite conductor. This model shows infrared signal dependence on the layer absorption and predicts topographic coupling into the infrared signal. The experimental data also indicate that a significant component in the infrared contrast arises from the problem following the samples topography and a method to eliminate the influence of topography following is demonstrated. The images corrected by such a procedure show spatial resolution approximately lamba/lOO. A more complex model based on a three dimensional finite difference time domain method was used to calculate scattering from an inhomogeneous surface.