Quasi-one-dimensional diffuse laser cooling of atoms

We demonstrate experimentally the generation of one-dimensional cold gases of $^{87}\mathrm{Rb}$ atoms by diffuse laser cooling. A horizontal slender vacuum glass tube with a length of 105 cm and diameter of 2 cm is used in our experiment. The diffuse laser light inside the tube, which is generated by multireflection of injected lasers, cools the background vapor atoms. With 250 mW of cooling light and 50 mW of repumping light, an evenly distributed 1-m-long profile of cold atom cloud is obtained. We observe a factor 4 improvement in the atomic optical density for a typical cooling duration of 170 ms and a sub-Doppler atomic temperature of 25 $\ensuremath{\mu}\mathrm{K}$. The central number of detected cold atoms remains constant for a free-fall duration of 30 ms. Such samples are ideal for many quantum optical experiments involving electromagnetically induced transparency, electronically highly excited (Rydberg) atoms, and quantum precision measurements.