Boston Chapter of the IEEE Photonics Society

Abstract:  The audience will first be introduced to the relevant physics of highly excited Rydberg atoms and how these atoms interact with electromagnetic radiation. I will then outline the potential uses of Rydberg atoms in advanced science and in practical applications, and how these atoms can be prepared for applications by trapping them in an optical lattice. An optical lattice is optically induced, micron-scale periodic crate in which the atoms can be localized at periodic lattice sites. Experimental results on the efficient trapping of cold Rb-85 Rydberg atoms in a one-dimensional optical lattice with laser wavelength 1064nm will be presented. The methods used to analyze the trapping efficiency and the atom dynamics include microwave spectroscopy and lattice-induced photo-ionization of a fraction of the atoms. In the second part of the talk, I will describe an optical-lattice setup suitable for the trapping of small particles (diameter of order 200nm) in water solution. The setup allows us to prepare dense, near-perfect optical crystals of thousands of these particles. I will show several lattice geometries as well as recent Bragg scattering results. The talk will conclude with an outline of possible applications of optically induced nano-particle crystals.

Biography:  Georg Raithel is a professor of Physics at the University of Michigan, where he teaches undergraduate and graduate-level courses, performs research and is involved in outreach activities.  In 1987 Dr. Raithel received his Diploma in Physics from the Ludwig Maximilian University of Munich.  His graduate research dealt with laser spectroscopy of Rydberg atoms in strong magnetic and electric fields. He earned his PhD in 1990.  From 1990 to 1995 Dr. Raithel conducted experiments on Rydberg atoms strongly coupled to high-Q microwave cavities. He completed his Habilitation in 1995.  From 1995 to 1997 he was a Feodor-Lynen fellow of the Alexander von Humboldt Foundation and researched in the atomic physics group at NIST/Gaithersburg on atoms in optical lattices.  In 1997 he accepted a position at the University of Michigan.  To date, 14 of his graduate students have received PhD degrees.  Dr. Raithel's research is focused on two main subjects: 1) Many-body quantum systems of cold Rydberg atoms.  These systems exhibit interesting coherence properties as well as strong electrostatic interactions, and they present a platform for quantum information processing.  2) Cold, guided atomic flows and Bose-Einstein condensation.  This research aims at realizations and applications of continuous-wave atom lasers, and at the study of the interactions of Bose-Einstein condensates with impurities.  3) The group also works on the trapping and manipulation of nano-particles in aqueous solution.  The research is described at http://www-personal.umich.edu/~graithel/ and http://cold-atoms.physics.lsa.umich.edu/. Outreach to the public is facilitated via publications, web materials, and programs targeting high-school students. Dr. Raithel has organized the 2009 and 2010 Michigan Physics Olympiads (see http://olympiad.physics.lsa.umich.edu/). Since Summer 2009 Dr Raithel is the Associate Chair for Research of the University of Michigan Physics Department.  Since January 2010 he is on the editorial board of the New Journal of Physics.  He is a Fellow of the American Physical Society (APS) and incoming Secretary/Treasurer of the DAMOP division of the APS. Dr. Raithel has about 70 peer-reviewed publications and has presented at numerous national and international conferences.