Secondary scattering on the intensity dependence of the capture velocity in a magneto-optical trap

In this work, we consider a three-dimensional model to simulate the capture velocity behavior in a sample of cold-trapped sodium atoms as a function of the trapping laser intensity. We expand on previous work [V. S. Bagnato, L. G. Marcassa, S. G. Miranda, S. R. Muniz, and A. L. de Oliveira, Phys. Rev. A 62, 013404 (2000)] by calculating the capture velocity over a broad range of light intensities considering the secondary scattering in a magneto-optical trap. Our calculations are in a good agreement with recent measured values [S. R. Muniz et al., Phys. Rev. A 65, 015402 (2001)].

Figure 1

Behavior of capture velocity as a function of the trap laser total intensity. The solid line is a simulation using the model described by Eq. (1) and shows that the capture velocity was supposed to increase with the laser intensity. The dashed line is only a guide to follow the experimental data of Ref. 1. [The experimental plot (dots and dashed line) is a courtesy of Muniz et al.]

Figure 2

Behavior of capture velocity as a function of the trap laser total intensity. As the intensity increases, the capture velocity reaches a maximum and then decreases, as shown by the experimental points (dots) measured by the authors of Ref. 1. The dashed line is, once again, only a guide to follow the experimental points of Ref. 1. The solid line is the simulation performed in the present work, using the model described by Eq. (4). By comparing the experimental data to our simulation, one can see a good agreement. [The experimental plot (dots and dashed line) is a courtesy of Muniz et al.]