Construction and investigation of a quantum frequency discriminator utilizing an 87Rb atomic beam with pumping and detection by injection lasers

An investigation was made of a quantum discriminator utilizing a beam of ⁸⁷Rb atoms with the pumping and detection performed by injection lasers which had external resonators. Design calculations were made for single- and two-frequency pumping of a beam of ⁸⁷Rb atoms. The signal/noise ratio was 15 000 in a band of 0.25 Hz and the Q factor was in excess of 20 when single-frequency pumping was used and a Ramsey resonance with a line width of 700 Hz was detected cyclically by a fluorescence method. The short-term instability of a frequency standard with these discriminator characteristics was estimated to be 5 X 10^–12τ ^–1/2 (where 1 < τ < 10⁵ s).