We discuss the quantization of the electromagnetic field in the presence of a perfectly reflecting parabolic cylindrical mirror. The mean squared electric field near the focus is calculated using a geometric optics approximation, and is found to grow as the inverse fourth power of the distance from the focus. This amounts to an enhancement of the vacuum fluctuations by geometric focusing. We show that the renormalized mean squared electric field can be either positive or negative, depending upon the details of the geometry. This leads to either an attractive or repulsive force, respectively, on an atom placed near the focus. We discuss some possible experimental tests of these results, including trapping of atoms near the focus by Casimir forces.
展开▼
