Month: December 2011

Ratiometric Imaging

Research activities are increasingly focusing on the identification and the spatial and temporal distribution of e.g. local “hot spots” for dynamic changes in ion concentration, voltage or pH in a cell or a cellular network. Such “hot spots” are often localized in specialized parts of a cell or in certain cells in a cellular network. …

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Beam Splitting

A completely different solution is possible by employing acousto optical devices [1]. As described in the tutorial about AOTF [2], the acousto optical crystal can be “excited” by a mechanical wave. The consequence of this mechanical excitation is the deflection of a very narrow spectral band (in the range of 1 … 3 nm) to a different direction …

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Spectral Imaging

The oldest method of (deliberately) separating colors of light was described by Sir Isaak Newton in his book “Opticks” of 1704: the employment of a prism. A copy of his drawing from that book is shown with the preface in this article. Today, our interpretation is that light of shorter wavelength will be diffracted at …

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Confocal Excitation

The light source for fluorescence excitation in confocal microscopes is a laser or a combination of lasers with varying color. Lasers are used for technical reasons [2]. Unfortunately, traditional lasers emit usually only a single wavelength, or a few lines only (a modern solution is the white light laser [3]). However, the fluorochromes used in …

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Videos on STED Microscopy and its Inventor Stefan Hell

YouTube by SPIETV, April 12, 2011 Using stimulated emission depletion microscopy and other techniques, Stefan Hell explores new ways to examine living cells noninvasively. Hell’s other accolades include the “Deutscher Zukunftspreis” (German Future Prize) for innovation and technology awarded by the German President (2006), the Gottfried Wilhelm Leibniz Prize from the German Research Foundation …

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