Distinguished Lecture Series in Physics
The UW-L DLS series in Physics is co-sponsored by the UW-L Foundation, Inc., the Department of Physics, the College of Science and Health, and Wettstein's. The purpose of the series is each year to bring to La Crosse a physicist whose significant accomplishments and communication skills can inspire and enrich the careers of students, faculty, and the community in general. Lectures are open to the public. Previous lectures
2011 DLS Speaker:
Dr. Theodor Hänsch
2005 Nobel Laureate in Physics
Director, Max Planck Institute for Quantum Optics
Professor, Ludwig-Maximilians University, Germany
Public Lecture
5 PM Thursday, November 3, 2011
Skogen Auditorium A, Room 1400, Centennial Hall
Passion for Precision
The Balmer spectrum of atomic hydrogen has provided the Rosetta stone for deciphering the strange laws of quantum physics during the early 20th century. Precise spectroscopy of the simple hydrogen atom can yield accurate values of important physical constants and it can stringently test basic physics laws. The invention of the laser frequency comb a decade ago has given us a tool for accurately counting the ripples of a light wave, so that we are now able to measure resonance frequencies in hydrogen to 15 decimal digits. Recently, it has become possible to perform laser spectroscopy of exotic muonic hydrogen, where the electron is replaced by a 200 times heavier muon. The measured 2S – 2P Lamb shift gives an accurate value of the charge radius of the proton. However, this radius is significantly smaller than the value obtained from spectroscopy of ordinary hydrogen or from electron scattering experiments. This proton size puzzle is the subject of intense discussions. It may be caused by a mistake, or it may indicate a dent in the armor of quantum electrodynamic theory.
Physics Colloquium
Open to the Public!
3:20 PM Friday, November 4, 2011
Room 100, Cowley Hall
What can we do with Laser Frequency Combs?
The spectrum of a mode-locked femtosecond laser consists of several hundred thousand precisely evenly spaced spectral lines. Such laser frequency combs have revolutionized the art of measuring the frequency of light, and they provide the long-missing clockwork for optical atomic clocks. High-harmonic generation with intense femtosecond pulses provides a path to extend frequency comb techniques into the extreme ultraviolet and perhaps into the soft x-ray regime. Laser comb techniques can give control of the electric field of ultrashort laser pulses, and they have become key tools for the emerging field of attosecond science. The availability of commercial instruments is facilitating the evolution of new applications far beyond the original purpose, ranging from fundamental research to telecommunications and satellite navigation. Laser combs are revolutionizing molecular spectroscopy by dramatically extending the resolution and recording speed of Fourier spectrometers. The calibration of astronomical spectrographs with laser combs will enable new searches for earth-like planets in distant solar systems, and may reveal the continuing expansion of space in the universe.
For a printable version of this year's DLS brochure, click here.
For a printable version of this year's DLS poster, click here.
For more information, contact :
Dr. Gubbi Sudhakaran, Chair
UW-L Department of Physics
(608) 785-8431
sudhakar.gubb@uwlax.edu