Harmonic holographic microscopy with circularly polarized excitation

We have developed a luminescent marker using the second harmonic generation (SHG) from noncentrosymmetric BaTiO3 nanocrystals. These nanoparticles are attractive due to their stable, non-saturating and coherent signal with a femtosecond-scale response time and broad flexibility in the choice of excitation wavelength. In this paper, we report the SHG response of BaTiO3 nanocrystals under a circularly polarized excitation. We observed a more uniform SHG signal intensity from nanocrystals of different crystal orientations under a circularly polarized excitation. The threedimensional (3D) SHG fields generated from the SHRIMPs were recorded by a harmonic holographic microscope. Submicron resolution in both lateral and axial directions has been achieved. We show that the circularly polarized excitation is useful for harmonic holographic microscopy. © 2009 SPIE-OSA.