Events at Physics |
Events on Thursday, November 1st, 2012
- R. G. Herb Condensed Matter Seminar
- Nonlinear and nonreciprocal effects in magnetic garnet films
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Pradeep Kumar, Michigan Technological University
- Abstract: The talk consists of two parts. In the first part, the lattice-imperfection and compositional origins of the nonlinear optical response in RF sputter deposited magnetic garnet thin films are discussed based on experimental findings. The experimental results establish that lattice mismatch strain drives the second harmonic signal in bismuth-substituted yttrium iron garnet (Bi:YIG) films, in agreement with theoretical predictions. This study also elaborates on the influence of the filmaEuroTMs constitutive elements and finds the nonlinear response to increase with yttrium concentration.
The second part of the talk addresses a novel effect, namely nonreciprocal optical Bloch oscillation, recently proposed and developed by us [1, 2]. Our work has established a comprehensive theoretical basis for the implementation of nonreciprocal and unidirectional optical Bloch oscillations. The model system we developed consists of one-dimensional waveguide arrays in silicon-on-insulator platforms with magnetic garnet cover layers. An optical force is introduced into the array through geometrical design, pushing the beam sideways. Laterally displaced photons are periodically returned to a central guide by photonic-crystal action, producing beam revival in the central guide. The unidirectional Bloch oscillation effect allows the implementation of on-chip optical isolation, a technologically important function in photonic integrated circuits [3].
[1] M. Levy and P. Kumar, Optics Letters Vol. 35, Issue 18, page 3147-3149 (2010)
[2] P. Kumar and M. Levy, Optics Letters Vol. 36, Issue 22, page 4359-4361 (2011)
[3] P. Kumar and M. Levy, Optics Letters Vol. 37, Issue 18, page 3762-3764 (2012)
- Host: McDermott
- Careers for Physicists
- Time: 3:30 pm
- Place: 4274 Chamberlin
- Speaker: Jim Haugen, IceCube
- Abstract: Jim Haugen received his B.S. in applied math, engineering, and physics at UW-Madison in 1983. He worked in the semiconductor industry in several locations including California and Thailand before coming back to Wisconsin to work at IceCube as a project manager. He will discuss his career path, and there will be plenty of time for Q&A.
- Host: Reina Maruyama
- Graduate Introductory Seminar
- Neutrinos, Dark Matter, and Fundamental Interactions
- Time: 5:45 pm
- Place: 2223 Chamberlin Hall
- Speaker: Balantekin, Heeger, Maruyama, Ramsey-ÂMusolf, UW Madison