Pictures of the Experiment

The small glowing dot at the center of the chamber is the fluorescence from about 10 million Cesium atoms which have been cooled down to a temperature of about 3 microKelvin (3 millionths of a degree above absolute zero). The quarter at the bottom of the chamber is there to show the scale of the atoms and the setup.

Vaccuum Chamber in OPTI 568. All glass cell with ultra high vaccuum. Picture from 1998. Since then a lot of optics, optomechanical components and magnetic field coils around it has been placed for the laser cooling and trapping of Cesium atoms inside this chamber (and nobody's taking them out anytime soon!) The UHV system is made entirely of quartz glass which provides excellent optical quality and does not introduce metallic or magnetizable material close to the atoms. This is important since a lot of the experiments here rely on accurate and fast magnetic field control. The pressure inside is about 10E-8 Torr which minimizes the chances of collision induced losses of the laser cooled atoms with the background environment inside the chamber.

Close up of Vacuum Chamber Picture of the glass cell with  surrounding optics and magnetic field generating coils. The white cylindrical structure contains coils (not seen here) in an anti-Helmholtz configuration to provide the MOT gradient fields. It also contains water cooling tubes  in thermal contact with the coils.  The cube glass like structure is actually made of plexi-glass and holds pairs of coils in a Helmholtz configuration for the generation of uniform magnetic fields in any arbitrary direction at a spot inside the chamber where the atoms are cooled and trapped. The setup ensures minimum amount of metallic and magnetizable material inside these coils. (Most of the metallic posts and optomechanical components seen here is outside the cube.)

The Science Area View of the experiment area from further away. To the left is a box made out of mu-metal shielding which houses the ion pump (not shown) that maintains vacuum at the chamber. The blue cables are optical fibers that channel laser light into the experiment. The optics for laser cooling surrounds the chamber and a CCD camera with appropriate imaging lens in the left captures part of the fluorescence from the atomic cloud. The large green bordered cage contains an additional set of coils in a Helmholtz configuration to cancel the earth's magnetic field at the region where the atoms are trapped.

The Complete Optical Table Complete view of the table-top setup for laser cooling and trapping. This view is zoomed out from the picture above and we can see the science area on the far center region of the picture. Closer on the left are 3 modules of home-built diode laser systems (white boxes) which provide laser light near the Cesium D2 line frequency, which is 852 nm. Much of the optical setup near these lasers are for frequency control and other diagnostics which include a setup for saturation spectroscopy, acousto-optic modulators and mechanical shutters. The laser light is then channeled to the experiment either in free space with mirrors or with optical fibers (not visible). Not shown in this picture are the computer control and an electronics rack for automation of the experiment and data-acquisition. These are out further to the left of the picture.

Experiment in OPTI 570 A more involved setup with the same principles as above but with lot more optics. Aside from the laser cooling and trapping lasers, this setup has additional optics for bringing laser beams from a Ti-Sapphire laser which provide about 1W of power to make a 3-D optical lattice at the vaccuum chamber to the right. (not visible). Click here to know more about optical lattices.

Laser Coolers (From left) Jae, Enrique and O hard at work getting all aspects of the setup running for some cool new experiments.

Made @ Home A major aspect of the experiments is building and assembling various electronic, software and optical components for the setup. Shown here is a collage of a few home built devices and functionalities. (From the left clockwise) 1. Computer, instruments and an electronic rack for automation and data-acquisition. 2. Close up of computer showing Labview and Matlab programs for control and signal analysis. 3. A home built fast balanced photo-detection electronic circuit on a printed circuit board (PCB) and with surface mount components for precision performance. 4. Inside a diode laser system with a diode (not shown here) and a grating forming an external cavity for better single mode performance. The red line drawn in this picture represents the path of the output laser beam. Also not shown here are the various electronics and optical components to further frequency stabilize the diode laser output