CESIUM BEAM ATOMIC CLOCK USING LASER OPTICAL PUMPING - PRELIMINARY TESTS.

A passive microwave cesium beam resonator utilizing optical pumping with a C. W. narrowband tunable laser (here, a GaAs laser) was realized. A population difference between the levels of the ground state hyperfine transition of **1**3**3Cs (at 9 192. 631. . . MHz) is achieved by optical pumping with the GaAs laser; the microwave resonance is detected through a change in the intensity of the fluorescence induced by the same laser. Preliminary tests of operation of the apparatus as an atomic clock were performed.