Application of scanning near-field optical microscopy to thin organic film devices

We previously developed a scanning near-field optical microscope (SNOM) for fluorescence microscopy and fluorescence spectroscopy by combining SNOM and atomic force microscope (AFM). In this combined microscope, a bent optical fiber with a sharpened tip end was used for simultaneous SNOM and AFM recording. In the present work, we used slim optical fiber probes with a diameter of 40 μm produced by etching in HF solution. Stiffness of previously used optical fiber cantilevers with 125 μm for SNOM-AFM was reduced dramatically. The slim optical fiber cantilever could be used for SNOM with tip–sample separation control by contact mode AFM. The contact mode AFM operation allowed simultaneous imaging of AFM, SNOM, and friction force microscopy. We will demonstrate application of such SNOM-contact mode AFM to the study of phase separation in Langmuir–Blodgett films without mechanical damage.