Non-linear niobate nanocrystals for two-photon imaging

In this work the infrared-to-visible second harmonic generation properties of powdered samples of three different niobate (Sr0.6Ba0.4Nb2O6, LiNbO3 and NaNbO3) nanocrystals were systematically investigated. Visible second harmonic radiation was obtained even for the smallest nanocrystals, of about 50nm, in a broad spectral range of fundamental wave illumination (700–1200nm). The influence of the host matrix, particle size and single phase on the infrared-to-visible second harmonic conversion efficiency was systematically analyzed. The results reported here open new perspectives for two-photon bioimaging by using non-linear nanocrystal probes as an alternative to the presently used fluorescent nanoprobes.