  Surface Quasi-Elastic Light Scattering (SQELS) is an application of dynamic
light scattering to measure the dynamics of the thermal roughness of liquid
surfaces. An analysis of the spectrum of thermal fluctuations provides
information on surface properties like tension and elasticity. In this work we
will focus particularly on its use to study polymer or polymer-like Langmuir
monolayers. We review work in this area and give an up-to-date overview of the
method. Important advances have very recently taken place in the theoretical
understanding of this problem, and this has allowed improvements in the
analysis of the experimental data. A practical method to estimate the region of
physical parameters that can be reliably measured is presented.
