Single structured light beam as an atomic cloud splitter

We propose a scheme to split a cloud of cold noninteracting neutral atoms based on their dipole interaction with a single structured light beam which exhibits parabolic cylindrical symmetry. Using semiclassical numerical simulations, we establish a direct relationship between the general properties of the light beam and the relevant geometric and kinematic properties acquired by the atomic cloud as it passes through the beam.

Figure 1

(Color online) Sampler of the transverse structure of the intensity of Weber em fields as defined by Eqs. (1). Even/odd em Weber fields with eigenvalues (a/d) $a=-2$, (b/e) $a=0$, and (c/f) $a=5$.

Figure 2

(Color online) Value for $u_M$, the coordinate that defines the parabola delimiting the low intensity region of a Weber field, as a function of the eigenvalue $a$. The length unit was taken as the wavelength of the beam and $k_z=0.995k$.

Figure 3

(Color online) Evolution of an atomic cloud as it interacts with an odd TE Weber beam whose intensity pattern is illustrated in black and white. The atoms initial velocities are mainly in the direction of the gravitational field, $v_x\sim -0.6m\lambda \Gamma$ with random $v_y$ and $v_z$ components, $\left|v_x\right|\ge 10v_{\perp }$, corresponding to $T\sim 1.5\mu \text{K}$. The Weber beam is characterized by $a=-5$, $k_z=0.995k$, and irradiance [(a) and (b)] 1.725 and [(c) and (d)] $6\text{W}/{\text{cm}}^2$. The atoms motion takes place within a $\sim 20\lambda$ wide region in the $z$ axis.

Figure 4

(Color online) (a) Absolute value of the deviation angle, $\theta =\text{arctan}y/x$ and (b) temporal evolution for the values of the mechanical property ${\mathbb{A}}_{\text{atomic}}=L_z{P}_y$ for different components of the clouds presented in Figs. 3a, 3b.

Figure 5

(Color online) Contribution to the kinetic energy from (a) velocities parallel to the gravitational force direction, $K_x/k_B=m{v}_x^2/2k_B$ and (b) velocities perpendicular to the gravitational force direction, $K_{yz}/k_B=m{v}_{\perp }^2/2k_B$, for different components of the clouds presented in Figs. 3a, 3b.