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Thursday, May 20, 2010

Two-Photon Quantum Dot Excitation during Optical Trapping

Liselotte Jauffred and Lene B. Oddershede

A single CW infrared laser beam can simultaneously trap and excite an individual colloidal quantum dot. Though the laser light is relatively weak, the excitation occurs through two-photon absorption. This finding eliminates the demand for an excitation light source in addition to a trapping laser in nanoscale experiments with simultaneous force-manipulation and quantum dot visualization. Also, we demonstrate that optical trapping efficiencies of individual quantum dots do not correlate with their emission wavelength or physical size.

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