Nanosecond nonlinear optical extinction in dispersed multi walled carbon nanotubes excited at 532 nm

Abstract

Experimental measurements of nonlinear optical extinction of nanosecond laser pulses by a set of conjugated co-polymer/multi walled carbon nanotube composites dispersed in solution is reported here. The polymer poly(meta-phenylenevinylene-co-2,5-dioctyloxy-para-phenylenevinylene) and multi walled carbon nanotube composites were varied according to nanotube mass content. The fabrication technique employed to produce the composite material is discussed. The experiments were performed using an open aperture Z-scan with 6 ns gaussian pulses at 532 nm from a frequency doubled, Q-switched Nd:Yag laser. The nonlinear optical extinction of the incident pulses displays enhanced dissipation of the incident light for lower incident intensities relative to increasing multi walled carbon nanotube content. Either the multi walled carbon nanotubes or the polymer dominates the nonlinear response of the composite depending on the relative mass of polymer to nanotube. Mechanistic implications of the optical dissipation are also discussed and investigated via angular dependent scattering measurements.