Measurement of nonlinear index by a relay-imaged top-hat Z-scan technique [report]

T. Shimada, N.A. Kurnit, M. Sheik-Bahae
1996 unpublished
Measurements of the nonlinear index of a number of materials of interest for the National Ignition Facility have been performed at 1064 nm and 355 nm by a modified version of the "top-hat" 2-scan technique and the results compared with the more standard gaussian-beam Zscan technique. The top-hat technique has the advantages of higher sensitivity and smaller uncertainties introduced by beam-quality considerations. We have made what we feel to be an additional improvement by placing the defining
more » ... acing the defining aperture for the top hat at the front focal plane of the lens that focuses the beam into the sample and then reimaging the input aperture with a second lens onto a ccd camera. Reimaging eliminates diffraction fringes and provides a stationary image even for a wedged sample; recording the entire image permits minimization of spurious effects such as varying interference fringes.
doi:10.2172/212526 fatcat:dw3kwf7zpve7di55x2du3yla4y