High quality optical resonators can store light and thus enhance the optical fields within the resonator by many orders of magnitude. High internal field intensities allow for efficient nonlinear processes and narrow linewidth resonances are ideal for precise sensing applications. A particularly interesting resonator is the whispering-Gallery-Mode resonator, which confines light based on the principle of total-internal-reflection in an azimuthally-symmetric dielectric. Crystalline materials feature low material absorption as well as high optical nonlinearities, including second order nonlinearities. I will present MgF2 resonators for bulk-index sensing and show how highly nonlinear LiNbO3 resonators can efficiently convert microwaves into optical radiation.

报告人简介：

Harald G. L. Schwefel received his Ph.D in theoretical physics from Yale University in 2004. He has since worked as a postdoctoral associate at Yale and in Japan. At the University of Erlangen-Nuremberg he completed his habilitation on the topic of "crystalline whispering gallery mode resonators". Currently he is a froup leader of an experimental group within hte division of Gerd Leuchs at the Max Planck Institute for the Science of Light in Erlangen, Germany. In September 2015 he will relocate to the Physics Department of the University of Otago in Dunedin, New Zealand as a senior lecturer and establish an independent research group. His current research interests are crystalline whispering gallery mode resonators, which he studies in the microwave, THz as well as in the optical domain. He is especially interested in non-linear optics and polarization within such resonators.