Continuous loading of magneto-optical trap of Rb at narrow transition

Abstract

We report continuous loading of ${}^{\text{87}}$Rb atoms in a magneto-optical trap (MOT) at narrow linewidth, 420 nm 5S${}_{1/2}$, F$=2\to$ 6P${}_{3/2}$, F$=3$ blue transition (blue MOT). Continuous loading of the blue MOT is achieved by superimposing the blue laser beam, inside a hollow core of infrared laser beam driving the broad 5S${}_{1/2}$, F$=2\to$ 5P${}_{3/2}$, F$=3$ transition at 780 nm. We typically load $\sim 10^8$ atoms in the blue MOT in 2.5 seconds. We characterize the continuous loading of blue MOT with various parameters such as magnetic field gradient, detuning, power and diameter of blue MOT beam and diameter of the hollow core (spot) inside the IR MOT beam. We observe that the blue laser beam should overfill the spot of the IR laser beam. This is because the blue laser cools the atoms to a lower temperature even in the presence of the broad IR laser i.e. in the overlapped region and hence helps in loading. We also present the theoretical framework for cooling atoms in the presence of simultaneously two transitions to support the experimental result. This method of continuous loading of the blue MOT can be useful to produce a continuous atomic beam of cold Rb atoms.

References in corpus (6)

• Narrow-line magneto-optical cooling and trapping of strongly magnetic atoms
• Core-Shell Magneto-Optical Trap for Alkaline-Earth-Metal-Like Atoms
• Two-stage magneto-optical trapping and narrow-line cooling of ${}^6$Li atoms to high phase-space density
• Narrow-line cooling of ${}^{87}$Rb using 5S${}_{1/2}\to$ 6P${}_{3/2}$ open transition at 420 nm
• Resolving closely spaced levels for Doppler mismatched double resonance
• Direct spectroscopy of Rubidium using a narrow-line transition at 420 nm

Cited by in corpus (1)

• Role of spontaneously generated coherence (SGC) in laser cooling of atoms