Abstract

Planar optics offer an easy method for highly increasing the sensitivity of optical multilayers to absorption and scattering from interfaces and bulks. In this aim we developed in Marseilles two techniques that enable to measure the attenuation of a guided mode inside a multilayer planar waveguide¹. The first technique is based on photothermal measurements that result from an absorption process, while the second involves a camera reading that registers scattering data. Though the principles of these two techniques are different, they should lead to the same value of attenuation coefficient, which is confirmed by experiment. At the present time these techniques allow to measure imaginary indices up to some 10^-8 at the wavelength 515 nm.

© 1995 Optical Society of America