The Physics department colloquia are usually on Friday afternoons at 3:30 pm in Lapham Hall Room 160. Coffee and cookies are served at 3:15 pm in the same room. Anyone is welcome.

Colloidal Crystals: Structure and Dynamics
Dr. Ivan A. Vartaniants DESY (Hamburg, Germany), National Research Nuclear Univ., MEPhi (Moscow)

Photonic crystals are important materials for the development of the present technology. They serve as photonic band gap materials in a wide range of light frequencies. Understanding the structure and dynamics of these materials with nondestructive methods is of high importance for different applications of these novel materials.

In this talk I will present our studies of the structure of colloidal crystals performed by coherent x-ray diffraction imaging method (CXDI). It will be demonstrated how arrangements of particles as well as individual defects can be visualized in 2D and 3D colloidal crystals with high resolution CXDI. Next, I will present studies of the colloidal crystals structure under incremental heating and in the end will discuss results of the pump-probe experiments performed at the free-electron laser LCLS in Stanford.