Photostable Second‐Harmonic Generation from a Single KTiOPO₄ Nanocrystal for Nonlinear Microscopy

Abstract

Single KTiOPO4 nanocrystals, isolated from a flux-grown powder, efficiently generate a perfectly stable and blinking-free second-harmonic field under non-resonant femtosecond optical excitation (see image). For each individual nanocrystal, size and three-dimensional orientation are determined using combined atomic force microscopy and optical techniques.