  Epitaxial thin films of LaFeAsO were fabricated on MgO (001) and
mixed-perovskite (La, Sr)(Al, Ta)O3 (001) single-crystal substrates by pulsed
laser deposition using a Nd:YAG second harmonic source and a 10 at.% F-doped
LaFeAsO disk target. Temperature dependences of the electrical resistivities
showed no superconducting transition in the temperature range of 2-300 K, and
were similar to those of undoped polycrystalline bulk samples. The
transmittance spectrum exhibited a clear peak at ~0.2 eV, which is explained by
ab-initio calculations.
