Abstract

At present, there exists no laser safety standard for retinal maximum permissible exposure (MPE) from laser systems capable of producing sub-nanosecond pulses in the visible or near infrared spectral region. Extrapolation of MPE levels from longer pulse widths is unacceptable since the high peak irradiances associated with ultra-short laser pulses are known to induce nonlinear material responses. To assess the effect that nonlinear propagation may have on the power densities at the retina, a sensitive and accurate method of determining the nonlinear refractive index in ocular media is required We report the measurement of the nonlinear refractive indices for cornea and vitreous humor using 2 picosecond, 580 nanometer laser pulses using the z-scan¹ technique.

© 1993 Optical Society of America