Population distributions in atom-laser interaction

C. J. Joachain

Farrokh Sarreshtedari, Alireza Rashedi, Fahime Ghashghaei +1 more

Abstract Incorporating the rate equations of the laser pumped atomic system, the population evolution of the Cesium Zeeman sublevels is calculated and discussed when a specific sequence of laser pulses irradiate the Cesium vapor. In this scheme, after the equalization of the sublevel populations by a magnetically resonant RF pulse, using a left (right) circularly polarized laser pulse the whole atomic population transfer to high (low) projection numbers. Then by irradiating a right (left) polarized laser pulse with appropriate duration and intensity, the desired population distribution could be obtained. The effects of different sequence parameters on the population distribution of Zeeman sublevels are investigated and it is shown that by proper process adjustment it is possible to arbitrary engineer the population distribution. Preparing the desired distribution of the population in the atomic sublevels is substantially important in different light–matter interaction experiments.

Noriaki Tsukada

We investigate atomic population dynamics of two Bose-Einstein condensate (BEC) states that are in different traps or in the same trap and are optically coupled through a common excited state by Raman laser pulses. For large interatomic interactions, almost all of the atoms that are initially in one of the traps (or one of the internal states) are either completely transferred into the other state or stay in the initially occupied state after the laser pulses, and the atoms (populations) are never distributed to both condensate states at the same time. Applications to the atomic logic gate and to output couplers of the atom laser are pointed out.

정도영, 이강수, 한재민 +3 more

S. Zielińska-Kaniasty

The velocity changing collisions (vcc) play an important role in the description of velocity redistribution of particles caused by nearly resonant interaction with the laser light and collisions (1). Collision relaxation rates are conveniently described by collision kernels which, in turn, depend on interatomic potential and scattering amplitudes and is proportional to the collision cross section. The population kernel gives the probability density per unit time that an active particle in state 1 i> undergoes collisions with perturbers (usually a noble gas atom or impurity), which changes the active particle velocity from v′ to v. Due to the fact that perturber-active particle interaction is state dependent the collisions cause different changes in the ground and excited states of active particle. Although the shape of the populations distributions resembles those from well-known Bennett hole theory, the distribution of the total population has two peaks and obviously is asymmetrical (2). Vcc together with velocity selective laser excitation lead to the asymmetry of the ground and excited state population. The flux of excited particles has properties which are different from that of ground state because of interaction collision potentials for both states. The intensity of the laser light strongly influences the velocity distributions of the ground and excited state populations.

Jean Dalibard, Claude N. Cohen-Tannoudji