Study on Ultrafast Photodynamics of Novel Multilayered Thin Films for Device Applications

摘要

During the summer of 2003, a picosecond Leopard YAG laser with an upgraded OPG system was purchased by the Laser Lab of the University of Puerto Rico, Mayaguez, after the contract award was announced. The laser arrived in August 2003, but due to problems with beam quality it was shipped back to the factory to be made right. The laser was corrected and was finally installed in the Laser Lab in mid-March 2004. The laser lab is now a well-established entity for the study of ultrafast photodynamic processes of optical materials. It functions in both an independent research role and a collaborative role in the development of optical materials. The primary focus of the project this year was on ultrafast spectroscopic studies of vanadium dioxide thin film as well as heavy metal nanoparticles embedded in melting glass optical materials. This effort included research on ultrafast passive optical switching derived by the enhancement of chi(exp 3), and ultrafast photo-induced insulator-metal transition (thermochromic effect). A large part of the initial focus was to develop heavy metal nanoparticle doped inorganic glass, which has been proven to show an enhanced chi(exp 3) effect. The other focal area was the study of the ultrafast phase-transition of VO2 thin film. This part of the work was begun right after the new laser was installed. With better laser output stability and beam profile, the authors were able to accurately characterize ultrafast time- resolved optical responses. (5 figures, 20 refs.).