Multiphoton Excitation of Upconverting Nanoparticles in Pulsed Regime

ZHIJUN CHEN; SI WU; JOSE HODAK; ROBERTO ETCHENIQUE

ANALYTICAL CHEMISTRY

AMER CHEMICAL SOC

Lugar: Washington; Año: 2016 vol. 88 p. 1468 - 1475

0003-2700

Upconverting nanoparticles (UCNPs) presentemission in the visible region upon irradiation with NIR lightthrough a multiphoton mechanism. However, the longcharacteristic time of their emission has prevented the use ofthis kind of entities as multiphoton probes. We present a studyon the use of erbium-containing UCNPs under pulsedexcitation, showing that both the power density and theduration of the excitation pulse are key factors to understandthe emission behavior. By adjusting power and excitation rate,we can obtain typical multiphoton z-axis focal exclusiveexcitation. These findings open the possibility of using UCNPsas probes for controlled localization of uncaging and imagingwith multiphoton z-axis sectioning. We show that this can beachieved even at power densities several orders of magnitude lower than traditional multiphoton microscopies.