z-scan measurement of the nonlinear absorption of a thin gold film Academic Article uri icon

abstract

  • We have used the z-scan technique at a wavelength (532 nm) near the transmission window of bulk gold to measure the nonlinear absorption coefficient of continuous approximately 50--thick gold films, deposited onto surface-modified quartz substrates. For highly absorbing media such as metals, we demonstrate that determination of either the real or imaginary part of the third-order susceptibility requires a measurement of both nonlinear absorption and nonlinear refraction, i.e., both open- and closed-aperture z scans must be performed. Closed-aperture z scans did not yield a sufficient signal for the determination of the nonlinear refraction. However, open-aperture z scans yielded values ranging from =1.9103 to 5.3103cm/W in good agreement with predictions which ascribe the nonlinear response to a Fermi smearing mechanism. We note that the sign of the nonlinearity is reversed from that of gold nanoparticle composites, in accordance with the predictions of mean field theories.

published proceedings

  • JOURNAL OF APPLIED PHYSICS

author list (cited authors)

  • Smith, D. D., Yoon, Y., Boyd, R. W., Campbell, J. K., Baker, L. A., Crooks, R. M., & George, M.

complete list of authors

  • Smith, DD||Yoon, Y||Boyd, RW||Campbell, JK||Baker, LA||Crooks, RM||George, M

publication date

  • December 1999