Nanowire nonlinear response and structural properties.

When a nanocrystal of noncentrosymmetric structure is optically excited at a fundamental frequency, it emits the optical signal at the exact doubled frequency. This phenomena is usually called second harmonic generation (SHG). Only materials with crystalline structures lacking a center of symmetry are capable of efficient SHG. Recently, alkaline niobate nanowires attracted lots of attention due to their extraordinary nonlinear response. The group of Prof. Aleksandra Radenovic (LBEN - Laboratory of Nanoscale Biology), in collaboration with Shenk Kurt from Laboratory of Crystallography (LCR), investigated the polarization dependence of SHG signal in trapped and stuck nanowires. This method might be used as a simple way to evaluate the degree of structural order and the c–axis orientation. The study also demonstrates efficient wave-guiding of SHG signal for the first time in all three types of X- NbO3 nanowires. Based on these nanowires extensive characterizations the authors suggest applications best matched to the nanowire nonlinear response and structural properties.

F. Dutto et al., Nano Lett., 11 (6), pp 2517–2521, DOI: 10.1021/nl201085b (2011)