Complex refractive index of polycarbonate over the UV-Vis-IR region from 0.2 to 3 µm.

The complex refractive index dispersion of polycarbonate was identified from reflectance and transmittance measurements across the spectral range of 0.2-3 µm. Two identification methods were investigated. A numerical identification method that allows rigorous consideration of different experimental configurations is described. The results obtained are compared with values calculated with an analytical method assuming normal incidence.

Note: Mechanical etching of atomic force microscope tip and microsphere attachment for thermal radiation scattering enhancement.

This Note describes a mechanical etching technique which can be used to prepare silicon tips used in atomic force microscopy apparatus. For such devices, dedicated tips with specific shapes are now commonly used to probe surfaces. Yet, the control of the tip morphology where characteristic scales are lower than 1 µm remains a real challenge. Here, we detail a controlled etching process of AFM probes apex allowing micrometer-sized sphere attachment. The technique used and influent parameters are discussed and SEM images of the achieved tips are given. Deceptive problems and drawbacks that might occur during the process are also covered.

Discontinuity induced angular distribution of photon plasmon coupling.

Metal-dielectric transitions are important structures that can display a host of optical characteristics including excitation of plasmons. Metal-dielectric discontinuities can furthermore support plasmon excitation without a severe condition on the incident angle of the exciting photons. Using a semi-infinite thin gold film, we study surface plasmon (SP) excitation and the associated electromagnetic near-field distribution by recording the resulting plasmon interference patterns. In particular, we measure interference periods involving SPs at the scanable metal/air interface and the buried metal/glass one. Supported by optical near-field simulations and experiments, we demonstrate that the metal/glass surface plasmon is observable over a wide range of incident angles encompassing values above and below the critical incident angle. As a result, it is shown that scanning near-field microscopy can provide quantitative evaluation of the real part of the buried surface plasmon wavevector.