  We describe Raman spectroscopy based method of measuring thermal conductivity
of thin films, and review significant results achieved with this technique
pertinent to graphene and other two-dimensional materials. The optothermal
Raman method was instrumental for the discovery of unique heat conduction
properties of graphene. In this method, Raman spectroscopy is used to determine
the local temperature of the sample while the excitation laser is utilized as a
heat source. The success of Raman spectroscopy in investigating thermal
conductivity of suspended graphene and graphene-based thin films motivated
extension of this technique to other materials systems and films.
