Enhancement of optical limiting response by embedding gallium phthalocyanine into polymer host

The need for materials to protect optical sensors from intense laser has resulted in intense research into passive phthalocyanine (Pc)-based non-linear optical (NLO) materials. The majority of optical limiting research is mainly focused on solution based studies over the past several decades, with fewer reports investigating passive solid-state non-linear optical devices. In this study, gallium phthalocyanine monomer (tBu4PcGaCl) and its μ-oxo-bridged dimer ([tBu4PcGa]2O) were embedded into a commercially available polymer poly(methylmethlacrylate) (PMMA) to produce composite films acting as passive solid-state optical limiters. The results show that Pc/PMMA composite display much larger non-linear absorption coefficient and lower saturable fluence for optical limiting when compared to the same Pc molecules in solution. No evidence of film fatigue or degradation was observed in the Pc/PMMA film after numerous scans at varying laser intensity.