Abstract

The measurement on energy levels suitable for time standards can be made more precise with the use of neutral atom manipulation techniques. We have created a fountain of atoms where the measurement time of atoms in ballistic free-fall can be on the order of a fraction of a second. With these long measurement times, the linewidth of the transition between the ground state hyperfine transition of sodium was measured to be 2 Hz. Transitions in the optical frequency range could then have Q's of 10¹⁴ to 10¹⁵. In addition to creating high Q resonances, it is desirable to have a continuous, high density fountain of atoms. Towards this end, we have constructed an "atomic funnel" capable of creating a cold, high flux stream of atoms suitable for injection into a continuous atomic fountain. In the first embodiment of the funnel, the brightness of the atomic beam (defined as the number of atoms per second/( Δv_xΔv_yΔv_z) was increased by a factor of 3 × 10³. With more recent improvements for both funneling more atoms from the hot atomic beam and better use of polarization gradient cooling to launch the atoms, we will describe how to improve the brightness enhancement by another four orders of magnitude.

© 1990 Optical Society of America