Three key technological developments were needed to make a portable trap a reality. The first, inexpensive and lightweight microwave modulation of diode lasers, had been developed by Paul Feng and was already in routine use in our research laboratory.
Subsequently, building on some ideas of Won Ho-Je in Korea, Rob Williamson and Paul Voytas developed a pyramidal trap that only requires one laser beam, with a resulting drastic simplification in the number and complexity of the optical elements.
Finally, Carl Wieman's group invented the DAVLL (Dichroic-Atomic-Vapor Laser Lock) method for simplified locking of a laser to an atomic resonance line (Applied Optics.vol.37, no.15; 20 May 1998; p.3295-8).
Exploiting these new technologies, in the fall of 1998 Ray Newell, a Physics graduate student, designed and built a portable magneto-optical trap. It is modular so that it can be broken down to fit inside a portable equipment case. It has been demonstrated to work, but its portability and reliability have yet to be tested. The total cost was about $14K, and the weight is less than 50 pounds.
The system can be broken down into three main components:
For more details, download Ray Newell's Master's Thesis.