We demonstrate back-to-back mirrors magneto-optical traps (MOT), thereby increasing access to the MOT and enabling stacked MOTs. Single-beam MOTs based on back-to-back mirrors will contribute to the development of compact and scalable cold-atom-based sensors.
A three-dimensional magneto-optical trap (MOT), acting as an efficient method for producing cold atoms from room-temperature atomic vapor, has been widely used to develop atomic sensors. Various compact MOTs using a single laser beam have been reported, simplifying apparatuses and leading to miniaturized devices. Here, we propose single-beam MOTs based on back-to-back pyramidal and conical mirrors. In such back-to-back mirrors, a MOT trapping volume is formed by an incident laser beam, a retroreflected beam, and multiple reflections from the mirror surfaces. We present the design of back-to-back mirrors and a series of compact MOT configurations, with the potential of increasing access to the MOT and simultaneously creating multiple MOTs. We demonstrate a MOT in a back-to-back conical mirror, loading \ensuremath{\sim}1 \ifmmode\times\else\texttimes\fi{} 10787Rb atoms from background vapor and cooling the atoms to \ensuremath{\sim}7 \textmu{}K using polarization gradients. Single-beam MOTs based on back-to-back mirrors contribute to building compact and scalable cold-atom-based sensors.
We present a novel and simple magneto-optical trap in pyramidal and in conical hollow mirrors, using a single beam. A diode laser having modulation sidebands at microwaves is used for cooling, trapping, and repumping of rubidium atoms in a vapor cell. When the laser is circularly polarized and sent into the hollow region, three pairs of counterpropagating beams are automatically produced therein that have the same polarization configuration as that of a conventional six-beam magneto-optical trap. The fluorescence by the trapped atoms and its mirror image are observed simultaneously. This system may be useful for atom-manipulation applications such as gravitational atom traps and atom waveguides.