Apertureless near-field optical microscopy: influence of the illumination conditions on the image contrast

Nanoscale Optical Microscopy and Spectroscopy Using Near-Field Probes

Light-matter interactions can provide a wealth of detailed information about the structural, electronic, optical, and chemical properties of materials through various excitation and scattering processes that occur over different length, energy, and timescales. Unfortunately, the wavelike nature of light limits the achievable spatial resolution for interrogation and imaging of materials to roughly λ/2 because of diffraction. Scanning near-field optical microscopy (SNOM) breaks this diffraction limit by coupling light to nanostructures that are specifically designed to manipulate, enhance, and/or extract optical signals from very small regions of space. Progress in the SNOM field over the past 30 years has led to the development of many methods to optically characterize materials at lateral spatial resolutions well below 100 nm. We review these exciting developments and demonstrate how SNOM is truly extending optical imaging and spectroscopy to the nanoscale.

Polarization filtering induced by imaging systems: effect on image structure

In this paper are reported the results concerning the experimental study of the interaction between the vectorial amplitude of an optical field and imaging systems. It is shown that far-field as well as near-field imaging systems beside their spatial frequency filtering ability, also act as polarization filters playing a determinant role on the image structure. This conclusion is drawn from an experimental and theoretical study involving a radially polarized Bessel beam used as a test object.

Chemical silver coating of fiber tips in near-field scanning optical microscopy

We report what is believed to be the first experimental demonstration of silver coating by a wet chemical process on tapered fiber tips used in near-field scanning optical microscopy. The process occurs at room temperature and pressure and takes only a few minutes to complete. Many tips can be coated simultaneously.