Photothermal absorption measurements in optical materials

Summary form only given. Photo-thermal common-path interferometry, referred to as PCI, has been used to study low absorption phenomena in optical materials with the goal of understanding their behavior under high average power laser illumination. This study included the measurement of low levels of optical absorption in commercially important linear and nonlinear optical materials. The behavior of these materials under high intensity illumination was found to be quite complex, with many showing not only a wide scatter in optical absorption, but also different types of photo-chromic nonlinear behavior that depend on power, time, sample history, etc. Representative data are summarized.