Efficient Optical Limiting in Carbon-Nanohorn Suspensions

Nonlinear optical properties of aqueous dispersions of single-wall carbon nanohorns(SWCNH) are investigated by a simple and original technique, relating nonlinear transmittance measurements with semi-empirical model fitting and allowing to identify the dominant nonlin-ear mechanism. The nanofluids shown a particularly strong optical limiting under irradiation by nanosecond laser pulses at 355, 532 and 1064 nm, much stronger than that previously reported in SWCNHs with smaller aggregate size. The effect is more relevant at 355 nm, where a nearly ideal optical limiting behavior with output energy practically independent on the input one is obtained,and it is attributed to the massive production of bubbles under the effect of light irradiation. This result opens interesting perspectives for the use of SWNCH-based suspensions for smart materials applications and green energy