Large nonlinear absorption in single aggregate of silver nanoparticles observed with z-scan imaging technique

Abstract

Although nonlinear optical spectroscopy of nanostructures, nanomaterials, and nanomedicines has been widely used to observe and study the nature of nonlinear optical (NLO) phenomena, the field has to improve for the single nanostructure system. However, it is extremely difficult to investigate the nonlinear optical behaviors of single nanostructure materials because the optical setup used in the experiment has to obligate a high resolution imaging arrangement and overcome the diffraction limit problem. This paper presents that a newly modified z-scan technique with imaging as a starting point for nonlinear optics measurement technology has been successfully implemented to investigate silver nanoparticle aggregation. Such single aggregation with a diameter of ∼1.56 µm made from silver nanoparticles has been precisely observed with an imaging profile on an aggregation target with a large nonlinear absorption coefficient of 8.90 × 109 cm/GW. This technique suggests a wide impact application for a better understanding and knowledge in conjunction with the origin of NLO behavior in any nanomaterials, including nanomedicines.