Nonlinear Absorption Studies of Disperse Orange Doped Polymer Film

Organic materials with substantial third order nonlinearity have become very important to protect the eyes and other sensors in high power laser applications. These materials are mostly based on the principle of reverse saturable absorption (RSA) where absorption cross section for excited state becomes more than the ground state. In such cases, the transmittance of the material decreases with increase in the intensity of laser beam. In this paper, we report the experimental results of Disperse orange-25 dye doped polymer films prepared using hot- press technique. Using open aperture z-scan technique we observe saturable absorption (SA) for disperse orange films at lower intensity and RSA at a higher intensity of 532 nm with a 6 ns and 10 Hz Nd:YAG laser beam . We have also studied the nonlinear response and optical limiting nature of the sample with CW and nano -second laser at 532 nm.