IONIZING COLLISIONAL RATE OF METASTABLE RARE-GAS ATOMS IN AN OPTICAL LATTICE

Ionizing collisional rate of metastable krypton and argon atoms in an optical lattice k(lattice) is compared with that in free space k(free) . Reduction of the collisional rate is observed for krypton atoms. How ever, the magnitude of reduction is no more than a factor of 2 at the laser detuning of 7 GHz. The ratio k(lattice)/k(free) is found to chan ge proportional to the square root of the excitation rate of atoms fro m the 1s5 metastable state to the 2p(9) state by the lattice laser. Th e mechanism that prevents a larger reduction is discussed.