Study and development of optical limiters

Author(s)

Newton Martins Barbosa Neto

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Física de São Carlos (IFSC/BT)
• Defense date: 2005-04-29

Examining board members

Sergio Carlos Zilio; Iouri Borissevitch; Tomaz Catunda; Wania da Conceição Moreira; Nilson Dias Vieira Junior

• Advisor: Sergio Carlos Zilio

Abstract

In this work, aiming to develop optical limiting devices, we have studied excited state absorption process in a group of tetrapyridyl porphyrins with different central substitutes (2H+, Zn2+, Ni2+, Cu2+). We have employed Z-scan technique with femto and picosecond pulses as well as with pulse trains to determine the excited state absorption dynamics and obtain some spectroscopic parameters like intersystem crossing time and triplet and singlet excited state absorption cross-sections. Moreover, we have developed a new geometry for an optical limiter, named multipass optical limiter. It is formed by two confocal spherical mirrors together with a plane mirror placed in parallel with the line joining them. (AU)