Room-Temperature Fluorescence Imaging and Spectroscopy of Single Molecules by Two-Photon Excitation
نویسندگان
چکیده
We report fluorescence imaging of single dye molecules on a glass substrate by two-photon excitation with femtosecond pulses from a mode-locked Ti:sapphire laser. The single-molecule images exhibit a high signal to background ratio (>30:1) and a high spatial resolution (fwhm < /3). A quadratic intensity dependence of single-molecule emission rate is experimentally verified, and single-molecule emission spectra are recorded with two-photon excitation. A comparison of photobleaching rates is made between one-photon and twophoton excitation schemes.
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