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BP: Fachverband Biologische Physik

BP 26: Posters II

BP 26.24: Poster

Thursday, February 28, 2008, 17:00–19:30, Poster A

Interferometric detection of nanosize diamond particles — •Thomas Wolf, Steffen Steinert, Carsten Tietz, Fedor Jelezko, and Jörg Wrachtrup — 3. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart

In recent years nanodiamonds have become available with well defined size distributions. It is possible to functionalize these diamonds with many different chemical groups to achieve biocompatibility and use them as markers. Aim of this work is to show the sensitivity of detecting scattering of these diamonds. We use a confocal setup combined with an interferometric detection scheme. The backscattered light of the sample passes the pinhole and is then recombined with the reference beam on our detector, thus yielding an interference pattern. As detector we use a splitted Si-diode to measure the difference signal. In this way it is possible to detect shifts in this interference pattern due to the light scattering of the diamonds. Using such a setup allows the detection of 50nm polystyrene or 10nm gold beads. The high refractive index of diamond should render it possible to detect diamonds down to a size of 10nm. Detecting this size would mean a step towards using nanodiamonds as non-toxic, non-bleaching biological markers.