Second harmonic generation from nanocrystals under linearly and circularly polarized excitations

Abstract

Abstract:We study second harmonic generation (SHG) from noncentrosymmetric nanocrystals under linearly polarized (LP) and circularly polarized (CP) excitations. Theoretical models are developed for SHG from nanocrystals under both plane-wave and focused excitations. We find that the focused excitation reduces the polarization dependency of the SHG signal. We show that the SHG response under CP excitation is generally inferior to the average of LP excitations over all orientations. We verify the theory by measuring the SHG polar responses from BaTiO 3 nanocrystals with a scanning confocal microscope. The experimental data agrees well with the theory. ©2010 Optical Society of America References and links1. I. Freund, M. Deutsch, and A. Sprecher, "Connective tissue polarity. Optical second-harmonic microscopy, crossed-beam summation, and small-angle scattering in rat-tail tendon," Biophys. J. 50(4), 693-712 (1986). 2. S. W. Chu, I. H. Chen, T. M. Liu, P. C. Chen, C. K. Sun, and B. L. Lin, "Multimodal nonlinear spectral microscopy based on a femtosecond Cr:forsterite laser," Opt. Lett. 26(23), 1909-1911 (2001). in polarization second-harmonic generation microscopy without specimen rotation," J.

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