Large non-linear absorption in C₆₀thin films

Abstract

The non-linear absorption coefficients of C60 thin films at 633 nm were measured with the absolute measurement and the Z-scan method, respectively. Both measurements yield a large non-linear absorption coefficient beta =4.4 cm W-1 and 8.0 cm W-1. A thermal self-focusing effect was also observed. The possible mechanisms of the larger non-linear absorption were discussed. The authors predict that C60 thin film may be a good optical limiter for a continuous wave (CW) laser.