Dynamic of optical nonlinearities in macromolecules and oligomers

Author(s)

Cleber Renato Mendonça

• Document type: Doctoral Thesis
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Instituto de Física de São Carlos (IFSC/BT)
• Defense date: 2000-10-20

Examining board members

Sergio Carlos Zilio; Cid Bartolomeu de Araújo; Douglas Soares Galvão; Jose Alberto Giacometti; Nilson Dias Vieira Junior

• Advisor: Sergio Carlos Zilio

Abstract

This work reports the dynamic nonlinear optical properties of organic compounds, namely, ytterbium bis-phthalocyanine, furfuryl alcohol derivatives and azo-aromatic compounds. In order to carry out this investigation we developed an experimental extension to the standard Z-scan technique, named Z-scan with pulse trains. In this method, pulse trains contained in Q-switched/mode-locked lasers can be advantageously used to study dynamic optical nonlinearities in the 10-1000 ns time interval, allowing the discrimination between fast and slow (cumulative) nonlinear effects. The results obtained in the compounds studied with this technique, complemented with linear optical measurements, permitted the nonlinear refraction and absorption origin to be determined, allowing the characterization of excited state spectroscopic parameters. (AU)