The market for thin films of complex oxides obtained by different deposition techniques is increasing exponentially in last decades due to large variety of possible application such as high-efficient solar cell, optoelectronic devices, etc. pulsed laser deposition (PLD) is a versatile growth technique and recently became more attractive for industrial applications due to the possibility to obtain crystalline thin films on a large area. Laser processing techniques were successfully used to obtain thin films with good optical properties starting from simple oxides, such as Sm 2 O 3 , ZrO 2 , etc., to more complex lead-free materials: Sr x Ba 1Àx Nb 2 O 6 (SBN) and Na 1/2 Bi 1/2 TiO 3À x%BaTiO 3 , or superconductive oxide YBa 2 Cu 3 O 7Àδ . When oxide thin films are designated for electronic and optoelectronic devices or for solar cells, the optical properties and the thickness must be well known. For this purpose, the spectroscopic ellipsometry technique was developed. Ellipsometry is a powerful technique to determine the optical properties of thin films especially when the thicknesses of thin films are in a nanometer range.