BaTiO<sub>3</sub> film is deposited on single crystal MgO substrate with pulsed laser deposition, and its crystal structure and surface roughness are characterized by X-ray diffraction instrument and atomic force microscope. BaTiO<sub>3</sub> film crystal quality is analyzed under three different oxygen partial pressure and three different annealing temperatures. The result shows that when the oxygen partial pressure is 15Pa, crystal surface (001) and (002) diffraction peak of BaTiO<sub>3</sub> thin films have higher intensity. It indicated that the film has a good c-axis orientation. When the annealing temperature is 800°C, the intensity of diffraction peak is the maximum, and peak shape is sharper. BaTiO<sub>3</sub> crystal film is obtained with highly preferred orientation, and film density is improved. Thus the film has less surface roughness and good crystalline state.
With the rapid development of optical testing technology, laser heterodyne interferometer has been used more and more widely. As the testing precision requirements continue to increase, the technical prism is an important component of heterodyne interference. The research utilizing thin film technology to improve optical performance of interferometer has been a new focus. In the article, based on the use requirements of interferometer beam splitting prism, select Ta<sub>2</sub>O<sub>5</sub> and SiO<sub>2</sub> as high and low refractive index materials respectively, deposit on substrate K9. With the help of TFCalc design software and Needle method, adopting electron gun evaporation and ion assisted deposition, the beam splitting prism is prepared successfully and the ratio of transmittance and reflectance for this beam splitting prism in 500~850 nm band, incident angle 45 degree is 8:2. After repeated tests, solved the difference problem of film deposition process parameters ,controlled thickness monitoring precision effectively and finally prepared the ideal beam splitting prism which is high adhesion and stable optics properties. The film the laser induced damage threshold and it meet the requirements of heterodyne interferometer for use.
Through the method of nonlinear optical frequency conversion method, 532nm, 355nm and 266nm laser wavelength can be attained by YAG1064nm laser. Mirror that works in this system must satisfy the requirements of high reflection in four bands. Based on the film design system to choose appropriate coating materials, adopting electron beam vacuum ion assisted deposition technique, through optimizing the parameters of the process, the film that reflectance is 99.8% at 1064nm , 99.6% at 532nm ,97.9% at 355nm and 96.8% at 266nm is prepared on the substrate of JGS<sub>1</sub>. Additionally, the laser induce damage threshold in the ultraviolet wave band is 1.432J/cm<sup>2</sup> at 355nm , 0.923J/cm<sup>2</sup> at 266nm. The results show that all the preparation of mirror meets the requirements well.