Spectroscopic infrared scanning near-field optical microscopy (IR-SNOM)

Scanning near-field optical microscopy (SNOM or NSOM) is the technique with the highest lateral optical resolution available today, while infrared (IR) spectroscopy has a high chemical specificity. Combining SNOM with a tunable IR source produces a unique tool, IR-SNOM, capable of imaging distributions of chemical species with a 100 nm spatial resolution. We present in this paper boron nitride (BN) thin film images, where IR-SNOM shows the distribution of hexagonal and cubic phases within the sample. Exciting potential applications in biophysics and medical sciences are illustrated with SNOM images of the distribution of different chemical species within cells. We present in this article images with resolutions of the order of λ/60 with SNOM working with infrared light. With our SNOM setup, we routinely get optical resolutions between 50 and 150 nm, regardless of the wavelength of the light used to illuminate the sample

New Materials and Technologies for Durability and Conservation of Building Heritage

The increase in concrete structures’ durability is a milestone to improve the sustainability of buildings and infrastructures. In order to ensure a prolonged service life, it is necessary to detect the deterioration of materials by means of monitoring systems aimed at evaluating not only the penetration of aggressive substances into concrete but also the corrosion of carbon-steel reinforcement. Therefore, proper data collection makes it possible to plan suitable restoration works which can be carried out with traditional or innovative techniques and materials. This work focuses on building heritage and it highlights the most recent findings for the conservation and restoration of reinforced concrete structures and masonry buildings

Infrared near-field microscopy with the Vanderbilt free electron laser: overview and perspectives

Scanning near-field optical microscopy (SNOM) makes it routinely possible to overcome the fundamental diffraction limit of standard (far-field) microscopy. Recently, aperture-based infrared SNOM performed in the spectroscopic mode,using the Vanderbilt University free electron laser,started delivering spatially-resolved information on the distribution of chemical species and on other laterally-fluctuating properties.The practical examples presented here show the great potential of this new technique both in materials science and in life sciences

Near-zone field effect of FIR laser radiation on tunnel current through the Schottky barrier under plasma reflection condition

Far infrared (FIR) radiation of high-power pulsed laser incident normal to the surface of GaAs/metal tunnel structures with a self-consistent Schottky barrier gives rise to a change in the tunnel conductance. It has been shown that the observed photoresistive effects are caused by ponderomotive forces of the radiation field on the free electron plasma in the junctions. The change of tunnel conductance rises linearly with increasing intensity at low power levels and proceeds into a strongly superlinear dependence at high intensities. It is shown that this superlinearity is a result of an enhancement of the local radiation field in the near zone of diffraction by inhomogeneities at the metal-semiconductor interface and depends strongly on the roughness of the metal electrode. Experimental results are compared to a nonlinear extension of the theory of electron redistribution due to the radiation pressure

The Effect of Immersive Audio Rendering on Listeners' Emotional State

Immersive audio rendering techniques allow for generating a 3D scenario where the listener can perceive the sound from all directions. An important aspect of these approaches is the subjective perception of the listener and how these types of systems are perceived from the emotional point of view and how they can influence the listener's mood. In this context, a deep investigation of immersive sound perception considering subjective perception in terms of flowing emotion is performed. Starting from a 4-channels immersive audio system and an emotion-aware system based on the analysis of the user's facial expressions, several experiments have been performed to investigate a correlation between immersive perception and the listener's emotions

An Experimentation to Measure the Influence of Music on Emotions

Several emotion-adaptive systems frameworks have been proposed to enable listeners’ emotional regulation through music reproduction. However, the majority of these frameworks has been implemented only under in-Lab or in-car conditions, in the second case focusing on improving driving performance. Therefore, to the authors’ best knowledge, no research has been conducted for mobility settings, such as trains, planes, yacht, etc. Focusing on this aspect, the proposed approach reports the results obtained from the study of relationship between listener’s induced emotion and music reproduction exploiting an advanced audio system and an innovative technology for face expressions’ recognition. Starting from an experiment in a university lab scenario, with 15 listeners, and a yacht cabin scenario, with 11 listeners, participants’ emotional variability has been deeply investigated reproducing 4 audio enhanced music tracks, to evaluate the listeners’ emotional “sensitivity” to music stimuli. The experimental results indicated that, during the reproduction in the university lab, listeners’ “happiness” and “anger” states were highly affected by the music stimuli and highlighted a possible relationship between music and listeners’ compound emotions. Furthermore, listeners’ emotional engagement was proven to be more affected by music stimuli in the yacht cabin, rather than the university lab

Free-electron-laser near-field nanospectroscopy

First experiments at the Vanderbilt free electron lasers measured the local reflectivity of a PtSi/Si system. The reflectivity in the scanning near-field optical microscope images revealed features that were not present in the corresponding shear-force (topology) images and which were due to localized changes in the bulk properties of the sample. The size of the smallest detected features clearly demonstrated that near-field conditions were reached. The use of different photon wavelengths (0.653, 1.2, and 2.4 mu m) enabled us to probe regions of different depth. (C) 1998 American Institute of Physics

Atonic force microscopy study of lymphoblastoid cells under 50-Hz 2-mT magnetic field irradiation

Atomic force microscopy (AFM) has been used to observe modifications induced by a 50-Hz 2-mT sinusoidal magnetic field on human B-lymphoblastoid cells (Raji). Cells exposed up to 64 h showed a drastic decrease in cell height during the first 13 h, reflecting the disappearance of microvilli, and a slower variation of the same parameter during the following 51 h together with a widening and loss of the cell's domed shape that corresponds to modifications at the cytoskeleton level