Measurement of pure Kerr nonlinearity in GaN thin films at 800 nm by means of eclipsing Z-scan experiments

We report the measurement of Kerr nonlinearity of thin films of GaN by using the eclipsing Z-scan technique. The measurement was performed using 100 fs pulses at 800 nm. We measured a pure refractive signal, whose associated nonlinear Kerr coefficient was n(2) = (-7.3 +/- 0.4) x 10(-14) cm(2) W-1.