For cold samples of laser-cooled atoms to be most useful in emerging technologies such as compact atomic clocks and sensors, it is necessary to achieve small sample sizes while retaining a large number of cold atoms. We consider achieving large atom numbers in a small system is a major challenge for producing miniaturized laser-cooled atomic clocks, since the number of captured atoms in a vapor-cell magneto-optical trap (MOT) scales as the fourth power of the laser beam diameter. This strong dependence on size is fundamentally set by the maximum spontaneous light force hbar k gamma /2, where hbar k is the photon momentum and gamma /2 is the maximum spontaneous photon scatter rate of a saturated transition of linewidth gamma. We are attempting to surmount the fundamental limit imposed by spontaneous emission by using bichromatic cooling, which is a technique that uses stimulated emission to slow the atoms. We have built a table-top experiment that uses stimulated-emission bichromatic cooling to pre-cool atoms and dramatically enhance the trappable atom number in a small MOT. We have designed the apparatus in a way that will let us test how bichromatic cooling scales with miniaturization. Here we report on our first experimental results of cooling a thermal beam of Rubidium atoms down to MOT capture velocities.
Proceedings Title: Proc. 2010 Intl. Freq. Cont. Symp.
Conference Dates: June 1-4, 2010
Conference Location: Newport Beach, CA
Pub Type: Conferences
atomic clocks, laser cooling