Measurement of nonlinear refraction index and two-photon absorption in a novel organometallic compound

We have determined the nonlinear refraction index [n(2) = -(6.6 +/- 0.7) x 10(-11) cm(2)/W] and two-photon absorption (TPA) coefficients [beta = (4.5 +/- 0.4) x 10(-8) cm/W] of a new kind of organometallic compound [Tp* Ir(CHCHC(CH3)(NH)(C2H5))] in dilute CH2Cl2 (1 x 10(-3) M) solution. The experiments where performed with a nanosecond-pulsed Nd-YAG laser at its second harmonic (lambda = 532 nm) radiation and employing the single- and dual-beam Z-scan techniques. The beam polarization, wavelength dependence and fast response time (tau < 7 ns) of the effect indicate that the observed nonlinearity near resonance is of electronic origin. This material also shows a good figure of merit [(2 beta lambda)/n(2) = 0.07] for its applications in all-optical devices in the nanosecond regime. Additionally, this organometallic is easy to synthesize, stable and exhibits no toxic and no pollutant properties. (C) 1998 Published by Elsevier Science B.V. All rights reserved.