Coaxial tips for infrared NSOM

We propose to use infrared light coupled with a near field scanning optical microscope (NSOM) to probe organic materials. The initial emphasis will be on the 2.8 - 3.25 μm range, which contains bands from both C - H and O - H stretching vibrations. This provides great sensitivity to specific chemical alterations as induced, e.g., in a photoresist by exposure and/or development. We have attempted to make IR NSOM probes by the fabrication of versatile coaxial nanostructures for their distinct use as waveguides supporting TEM modes free of frequency cut-off. We have modeled a conical coaxial structure for its losses at target areas with 2.8μm wavelength. Preliminary results indicate their potential as efficient and reproducible probes.