Absolute frequency measurement of the cesium D/sub 2/ line

We describe a scheme of absolute frequency measurement of the cesium-stabilized diode laser at 852 nm based on the absolute frequency standard of /sup 87/Rb at 780 nm and well stabilized CO/sub 2/ laser at 9.23 /spl mu/m. The frequency of the CO/sub 2/ laser is stabilized to the center of the 4.3-/spl mu/m saturated fluorescence with frequency instability of 5 kHz. Two diode lasers are stabilized to the center of D/sub 2/ saturated absorption line of Cs at 852 nm and to the center of D/sub 2/ line of /sup 87/Rb at 780 nm with accuracy about 30 kHz, respectively. The sum frequency of the 852 nm and 9.23 /spl mu/m radiation is beated against the 780 nm radiation to obtain the absolute frequency of the Cs D/sub 2/ line. The sum-frequency generation and beat frequency experiment will be finished in the near future and reported in the conference.