Graphene Oxide And Titanate Nanobelts On Optical Limiting

With the wide use of laser applications in various fields,laser threat to cause damage to the human eye and precision optical instruments are becoming increasingly serious.Accordingly, optical limiting(OL) materials for the purpose of laser protective are concerned.It is becoming one of the hottest field in the current material science that improving the performance of existing OL materials,finding a nonlinear optical mechanism and exploring and designing new OL materials.In this thesis,we firstly used the improved Hummers method to prepared GO and GO liquid crystal, prepared graphene oxide (GO)-chitosan(CS) composite by solution blend method, and then filmed by czochralski method, and study the OL effects and mechanisms; then, tested OL properties of gold/silver nanoparticles modified titanate nanobelts (TNBs) by Z-scan technology and discussed their OL mechanisms.The results show that with the increase of the incident energy, the OL properties of GO aqueous solution gradually strengthen; and as the concentration of the suspension increases, OL performance enhanced significantly. Because of low linear optical transmittance of GO liquid crystal, there is not a reasonable nonlinear optical test results obtained. The OL mechanisms of the GO-CS composite were studied by using Z-scan technology. During the nonlinear optical limiting mechanisms of the composite film the contribution of nonlinear absorption enhances and the role of the nonlinear scattering decreased because a synergistic effect on CS small π electron system and GO large π-electron system.Without affecting OL performance of GO,film formation and solid-state of graphene in this way can provide a theoretical and practical basis for graphene practicality.In addition, we find the OL properties of TNBs modified with gold/silver nanoparticles. The result shows that the composites have a lower OL threshold and obvious OL effects. Because of the charge/energy transfer between gold/silver nanoparticles and TNBs,the OL effects of the composites were further enhanced.