We present an experiment on the measurement of the spatial distribution of cold atoms in a ceramic cell. The atoms are first cooled by diffusing light produced by multiple scattering of laser light at the inner surface of the cell. An in homogeneous magnetic field is applied after the atoms are cooled by using a pair of anti-Helmholtz coils, and thus the shift of atomic magnetic sub-levels is position-dependent. We move the anti-Helmholtz coils point by point while keeping the probe laser beam resonant with the cold atoms at zero magnetic field. The number of cold atoms at different positions can be extracted by detecting the absorption to the probe beam. The density of the cold atoms in the cell is measured in two dimensions perpendicular and parallel to the tube connecting to the vacuum system, respectively. The results show that at the center of the cell, fewer atoms exist due to the leakage of diffuse light into the hole connecting to the vacuum pump. The method we developed is used to detect cold atoms in a region where imaging is impossible.

积分球内漫散射光对铷87原子冷却的装载过程研究;积分球内漫散射光对铷87原子冷却的装载过程研究;Loading of cold87Rb atom with diffuse light in an integrating sphere

Measurement of Spatial Distribution of Cold Atoms in an Integrating Sphere

Dielectric spheres moving in a dissipative medium are subjected to the effects of optical binding, i.e., a net force resulting from the collective scattering of light. Optical binding is now shown to exist with frictionless cold atoms, bringing as an additional feature the existence of rotating bound states.

Optical binding with cold atoms

The integrating sphere is used to generate the diffuse light for cooling atoms. The microwave field is produced in a cylindrical cavity on a TE011 mode. We have realized the microwave interrogation with the pulsed optically pumped (POP) scheme. The Ramsey fringe is demonstrated and some factors to affect the signal to noise ratio (SNR) and the contrast of the fringe are discussed. Optimization of the experimental parameters is still in progress.

Integrating sphere cold atom clock with cylindrical microwave cavity

Increasing the cold atom density in an integrating spherical cavity

We discuss theoretically the optical binding of one-dimensional chains of cold atoms shone by a transverse pump, where particles self-organize to a distance close to an optical wavelength. As the number of particles is increased, the trapping potential increases logarithmically as the contributions from all atoms add up constructively. We identify a cooperative cooling mechanism, due to the mutual exchange of photons between atoms, which can beat the spontaneous emission for chains that are long enough. Surprisingly, the cooling is optimal very close to the resonance. This peculiar cooling mechanism thus gives new insights into the cooperative physics of low-dimensional cold atom systems.

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积分球内漫散射光对铷87原子冷却的装载过程研究;积分球内漫散射光对铷87原子冷却的装载过程研究;Loading of cold87Rb atom with diffuse light in an integrating sphere

Citations

Measurement of Spatial Distribution of Cold Atoms in an Integrating Sphere

Optical binding with cold atoms

Integrating sphere cold atom clock with cylindrical microwave cavity

Increasing the cold atom density in an integrating spherical cavity

Cooperative cooling in a one-dimensional chain of optically bound cold atoms