Heat-Induced Dip of Optical Limiting Threshold in Carbon Nanotube Aqueous Suspension

Carbon nanotube (CNT) suspensions possess nonlinear light scattering, which leads to a manifestation of the optical limiting (OL) phenomenon. Here we present the results of research into the temperature influence on the OL of multiwalled CNT suspensions. The experiments were carried out with a stable aqueous suspension of chemically treated CNTs synthesized by graphite arc evaporation. The OL study was performed by a z-scan technique using a 532 nm single-mode nanosecond laser. An increase in the suspension temperature by 17 °C from 23 to 40 °C was found to result in 3 times reduction of the OL threshold intensity of the suspension. Upon further heating, the OL threshold remains constant. The analysis of the results obtained is presented. Our experimental findings allow one to reveal the optimal temperature range for an optical limiter based on aqueous CNT suspension