Feb. 06, 2012

Near-Field Microscopy with Superlenses

Conventional imaging devices are limited in their resolution and, hence, restrict the insights into structures smaller than the wavelength. Near-field microscopy overcomes this limitation by probing evanescent fields resulting in a wavelength-independent resolution. A superlens is a planar device, which transforms these fields to an image plane. We study such lenses for the infrared based on perovskite oxides, which might be applicable to imaging of highly-damped samples e.g. in liquids. moreJan. 30, 2012

The Power of ImageJ

In 1997 Wayne Rasband, computer scientist at the National Institutes of Health (NIH, Bethesda, USA), released the first version of ImageJ. It is the successor of the image processing software NIH Image, which was well known at this time. NIH Image was exclusively tied to the Macintosh platform, the new software, however, is independent from platforms since it is completely programmed in Java, the lingua franca in the computer world. moreJan. 23, 2012

Principal Component Analysis in Dynamic Force Spectroscopy

A simple method to direct identify nanometer sized textures in composite materials by means of AFM Spectroscopy, aiming at recognizing nanometer structures embedded in a sample. It consists in acquiring a set of dynamic data organized in spectroscopy maps and subsequently extracting most valuable information by means of the Principal Component Analysis (PCA) method [1]. In this work we explain the main features of the method and show its application on a nanocomposite sample. Force Spectroscopy by AFM moreJan. 16, 2012

Triple-Frequency Atomic Force Microscopy

It has previously been shown that bimodal tapping-mode AFM can provide increased compositional contrast. Here we discuss the addition of a third eigenmode to this scheme in order to acquire simultaneous topography, phase and frequency shift. The results suggest that, in general, the phase and frequency shift contrast exhibit anti-parallel behavior, although deviations from this trend are often observed in the experiments, such that all sources of contrast can provide complementary information. Multi-Frequency AFM moreDec. 27, 2011

Time-Gated STED Microscopy

Stimulated emission depletion microscopy has been used to overcome the diffraction limit of confocal fluorescence microscopy. By exploiting information present in the arrival time of fluorescence photons through time-gating, the resolution of STED microscopes can be improved significantly. The resolution improvement of this technique - termed "T-STED" - becomes most evident in CW-STED where the STED beam is of long duration compared to the lifetime of the fluorophore.

Introduction
moreDec. 19, 2011

Multifrequency Atomic Force Microscopy

Multifrequency Atomic Force Microscopy (AFM) involves several force microscopy methods that aim to improve spatial resolution, data acquisition times and quantitative mapping of surface properties with respect to the level that has been achieved by conventional AFM. About twenty years ago, amplitude modulation AFM (tapping-mode) was introduced to avoid the sample modifications introduced by lateral forces that existed during contact AFM operation. moreDec. 05, 2011

Tip Mass Effects on Image Contrast

When an oscillating AFM cantilever approaches a sample, the tip-sample interaction force influences the cantilever dynamics. The magnitude of the contact interaction force depends on the stiffness of the materials. Stiffness of the material affects sensitivity of different modes differently. This sensitivity controls the image contrast. Here, the effect of tip mass on the modal flexural sensitivity of AFM cantilever to the variations of surface stiffness and image contrast is investigated.
moreNov. 28, 2011

Core Facility Management

Managing an imaging core facility with numerous microscopes and many ever-changing users requires tools that track user contact and project data, allows easy communication between facility users and staff, and monitors the performance of the microscopes. Commercial tools are too general for these specific tasks, thus we developed a customized Core Facility Management tool-box that includes a user database, online user registration and contact forms, booking and trouble ticket system and a Wiki.
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