Experimental Setup

Rubidium Vapor Cell

A close-up view of a rubidium vapor cell. In the background is a foil-wrapped cell-heater containing a similar glass vapor cell. Click for a lerger picture with a wider field-of-view.Photo by Jim Wallace, Duke University Photography, © 2005.

The specific light-matter interactions we exploit in our experiment arise from laser beams that shine onto a vapor of rubidium atoms. Although natural air is a collection of atoms (and molecules, dust etc.), in order to have a medium that interacts readily with laser light we use a vapor containing only one type of atom. In order to isolate a monatomic vapor (atomic gas containing only one type of atom) we create a vacuum within a glass cell and then add rubidium in vapor form. The glass tube connecting the rubidium source and the cell is then pinched and sealed shut to keep the rubidium atoms in and the air out. An example of a rubidium cell is shown on the right, held in front of our actual experimental setup.

The background of the picture shows aluminum foil which is wrapped around a collection of heating elements and insulation used to heat a vapor cell. This gives us control over the temperature of the vapor cell which is directly related to the density of the rubidium vapor. A specific temperature (roughly 72 celsius) corresponds to the ideal atomic number density for the pattern-forming interactions used in our research.

Optics

Photo by Jim Wallace, Duke University Photography, © 2005.

A bird's eye view of the optical table and experimental setup used in our research. In the center-left of the photo our foil-wrapped vapor cell is seen centered within helmholtz magnetic coils used to cancel the axial component of the Earth's magnetic field.

The background of the photo shows our pump laser (far right) pumping a Ti:Saph laser (top) used for this experiment and many others.

A portion of the switching-beam path can be traced from the lower center of the photo to the upper left toward the pump laser. The coiled fiber in the bottom of the picture transports the switching beam from one part of the table to another. Two beamsplitters used in the experiment can be seen in the center of the photo; one is a glass cube roughly half an inch wide, the other roughly one inch wide.