A Laser Trap for Neutral Atoms.

This project constructed and studied a laser trap for neutral atoms, initially potassium (K). At low densities, such a trap could be used to address a number of fundamental questions, e.g. the interaction of an individual atom with an electromagnetic field, collision dynamics and recombination. The feasibility and limitations of a purely laser trap concept, a corner cube trap , for trapping neutral K atoms are studied. The confinement of the atoms in the two dimensions perpendicular to the laser is provided in the cavity of a newly constructed high power alexandrite laser operating in the (doughnut mode) tuned slightly to the blue side of the resonance line of the K atom. By reflecting the laser back on itself with two mirrors, one caps the ends of the cylindrical trap, resulting in a slightly weaker end plug. Examined are various loss mechanism for the trapped atoms. In particular, K atoms are lost to the trap if they are multiphoton ionized, if they are heated by absorption and emission of many photons, if they simply have much higher energy than the vast majority of other atoms at 1.5 K, or if they recombine with He to form KHe (or KHe2, etc).