Laser System Construction and Testing

To trap atoms successfully requires developing expertise in ultra-high vacuum systems, laser technology, feedback control techniques, and magnetic field and optical design. Our experience at BCIT has shown that we have the requisite wealth and depth of expertise required to meet the challenges of an atom trap.

 

 

 

 

Top view of the diode lasers constructed at BCIT for atom trapping.

 

 

 

 

 

 

 

The first task was the construction of two diode laser systems at BCIT following the prescription of Wieman et al. [1]. To trap atoms, the lasers' frequencies have to be carefully tuned and locked close to the atomic rubidium resonant energy. (For a more detailed description see [1, 2], for example.) This necessitated that the laser frequency must be held stable to a few parts in a billion. To achieve this requires that the laser must be constructed with care to reduce the effects of acoustic vibration, temperature drift, and current fluctuations --- and attainable through active feedback circuits and thoughtful mechanical design.

The mechanical housing and piezo-electric feedback design was carried out by Glenn Lewis (Technician, BCIT Physics) while the electronic systems were built by Wayne Pogue and Yang Wang, two biomedical engineering students. Under the supervision of Bruno Jaggi (faculty, BCIT Biomedical Engineering) and Joe Newton (supervisor, BCIT Technology Center), Wayne and Yang constructed the laser current supply, temperature control circuit, and the servo-locking circuit published in [1, 2] as part of their senior project. Their work involved breadboarding and bench testing of the circuitry, and the creation and population of PC boards used in the laser systems. Their dedicated efforts were crucial to the success of this work.