Control of Cross-Sections and Optical Nonlinearity of Pt Nanowires and the Roughness Effect

Y Ogata,G Mizutani

doi:10.1155/2012/969835

Abstract

In this paper we review our fabrication of Pt nanowire arrays on MgO(110) faceted templates by a shadow deposition method and our control of their cross-sectional shapes by adjusting the deposition directions of platinum. We obtained nanowire arrays with Cs and C2v macroscopic symmetries. These macroscopic symmetries influence optical second harmonic generation (SHG) susceptibility elements of the nanowire arrays sensitively. On the other hand, the roughness of the nanowires had an effect on the rotational SHG patterns as a function of the sample rotation angle around the surface normal. We tried to explain the pattern change by a second-order perturbation scheme with respect to the roughness amplitude.

Highlights

IntroductionOptical second harmonic generation (SHG) is a coherent nonlinear optical process and its efficiency depends upon the electronic properties and upon the symmetry of the geometrical structure of the medium [1,2,3]
The facet formation of the surface was confirmed by reflection high-energy electron diffraction. Both Pt nanowires with the elliptic and boomerang-like cross-sectional shapes on the faceted MgO(110) templates were fabricated by the shadow deposition technique in a UHV chamber with base pressure of 9.5 × 10−7 Pa
Later in this paper one will find that these imperfections influence the second harmonic generation (SHG) response of the Pt nanowires

Summary

Introduction

Optical second harmonic generation (SHG) is a coherent nonlinear optical process and its efficiency depends upon the electronic properties and upon the symmetry of the geometrical structure of the medium [1,2,3]. Schider et al investigated linear optical properties of metallic nanowires prepared by electron beam lithography systematically [6]. SHG properties of Au and Pd nanoparticles and Au connected nanoparticles were studied [8,9,10] They analyzed the observed enhancement of the SHG intensity by using RCWM (rigorous coupled wave method). SHG from metal nanocylinders was investigated in detail by using numerical electromagnetic simulation of the electric quadruple excitation [11] They discussed the local field enhancement by surface plasmon polariton modes in the metallic nanorods.

Asymmetry in direction 3 remains

Experimental

Results and Discussion

Conclusion