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PubMed · 9726953

Continuous wave two-photon scanning near-field optical microscopy.

A K Kirsch·V Subramaniam·G Striker·C Schnetter·D J Arndt-Jovin·T M Jovin
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Abstract

We have implemented continuous-wave two-photon excitation of near-UV absorbing fluorophores in a scanning near-field optical microscope (SNOM). The 647-nm emission of an Ar-Kr mixed gas laser was used to excite the UV-absorbing DNA dyes DAPI, the bisbenzimidazole Hoechst 33342, and ethidium bromide in a shared aperture SNOM with uncoated fiber tips. Polytene chromosomes of Drosophila melanogaster and the nuclei of 3T3 Balb/c cells labeled with these dyes were readily imaged. The fluorescence intensity showed the expected nonlinear (second order) dependence on the excitation power in the range of 8-180 mW. We measured the fluorescence intensity as a function of the tip-sample displacement in the direction normal to the sample surface in the single- and two-photon excitation modes (SPE, TPE). The fluorescence intensity decayed faster in TPE than in SPE.

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3T3 CellsAnimalsBiophysical PhenomenaBiophysicsCell NucleusChromosomesDrosophila melanogasterFluorescent DyesIndolesMiceMicroscopy, FluorescencePhotonsJournal ArticleResearch Support, Non-U.S. Gov't

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A K Kirsch, V Subramaniam, G Striker, C Schnetter, D J Arndt-Jovin, T M Jovin. 1998. Continuous wave two-photon scanning near-field optical microscopy.. https://doi.org/10.1016/s0006-3495(98)74070-6

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