Second Harmonic generation from an array of gold nanocylinders up to a single nanocylinder

1.    Nonlinear response of an array of gold nanocylindersThe second harmonic generation process has been performed from hexagonal array of gold nanocylinders. The nonlinear response has been carried out as a function of the... [ view full abstract ]

1.    Nonlinear response of an array of gold nanocylinders

The second harmonic generation process has been performed from hexagonal array of gold nanocylinders. The nonlinear response has been carried out as a function of the input fundamental polarization angle for the on and off –axis transmission geometries and crossed output polarization configurations and for different diameter sizes. The nonlinear response is essentially incoherent in an on-axis transmission geometry while a coherent response appears on off-axis configuration. Indeed for the on-axis configuration the breaking of symmetry shape of the cylinder body leads to a pure electric dipole incoherent response. On the other hand, considering small tilt angle the nonlinear coherent contribution appears from the out-of-plane non linearity. It has also to be noted that as a function of the nanocylinder size the retardation effect play an important role.

2.    Nonlinear response of an individual gold nanocylinder.

We have also performed nonlinear studies up to an individual nanocylinder as is displayed on the figure 2. Each gold nanocylinder appears as a circular SHG intensity distribution. This individual mapping indicates clearly that the nonlinear response is due like an array of nanoparticles to the defects at the surface and not to the longitudinal symmetry and the size.