Winter 2014


Friday 10 January
Youngchild 115

*Preceded by Physics Tea at 3:30 pm in Youngchild 104*

Erik Brekke, St. Norbert College
“Atom-Light Interactions: Generating New Coherent Light Sources”

The laser has become both a very common and important technology.  However, there are still important frequencies where effective lasers are hard to develop.  In this talk I will explore one method for developing novel laser sources, called parametric four-wave mixing.  By controlling the interaction of existing laser sources with rubidium atoms, it is possible to have coherent light emitted using transitions between atomic levels.  The limiting factors to high power output will be discussed, as well as possible solutions.  Current experiments have shown the realization of this process at 420 nm, a desirable wavelength for quantum computing.

Fall 2013

The 2013-14 year is under way.  Welcome to our new physics students and welcome back to our returning students.

Keep an eye on this page for Physics Department news items.

And, take a look at the Fall 2013 edition of the Departmental Newsletter.

Wed 14 Aug 2013: Summer Symposium

Stay tuned for the details.

Sa 15 Jun 2013: Physics Open House

The Department of  Physics will hold an Open House reception during Reunion weekend in Youngchild Hall Room 115 from 9:00 AM to 10:00 AM.

Tu 11 Jun 2013: Summer Research Program

The physics summer research program kicks off at 9:00 AM in YC-115.

Tu 28 May 2013: Senior Tea

This year's Physics Senior Tea will take place on

Tuesday 28 May 2013 at 4:30 PM in the Esch-Hurvis Room at the Warch Campus Center.

We will celebrate the accomplishments of and extend our best wishes to the graduating physics majors and minors and departing engineers.

W 22 May 2013: Physics Colloquium

Dr. Rob Salgado
Department of Physics, Lawrence University

Relativity on Rotated Graph Paper


Minkowski Spacetime diagrams have been difficult to interpret because line segments representing equal spacetime-intervals have unequal Euclidean lengths. However, it turns out that the areas of their respective "causal diamonds" are equal [in both Minkowskian and Euclidean geometries]. (The causal diamond of a timelike segment is the intersection of the causal-future of the past-endpoint with the causal-past of the future-endpoint. This appears as a parallelogram with lightlike edges, with the segment as a diagonal. Physically, this represents one tick of an inertial observer's light-clock.) Using rotated graph paper, we develop a physically-motivated geometrical method to do the standard calculations in special relativity---by counting boxes and using a minimal amount of algebra. This has been used to teach relativity to introductory physics students. (A draft of my article is available at: It is undergoing substantial reorganization.) We conclude with my current efforts to extend this method to uniformly-accelerated observers. [Graph paper and colored pens will be provided.]


Wednesday 22 May
Youngchild 115

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