Interferometric studies on thin photoactive polymer films

Due to the importance of measuring the refractive index of optical waveguides, it is very important to find an accurate method to model the operating characteristics properly. The optical properties of thin photoactive polymer films are studied interferometrically using two different techniques, two and multiple beam. It is shown that the refractive index and birefringence of Disperse Red 1 doped with poly(methyl methacrylate) are independent of either the thickness of the film or the type of solvent used. A comparison between the two- and multiple-beam interferometric techniques for the determination of refractive index and birefringence is given. Both methods are evaluated and microinterferograms are given for illustration. Another comparison between the interferometric techniques and prism coupling technique is also given.