Application of Laser - Cooled Ions to Frequency Standards and Metrology '

With the first experiments on laser cooling, it was realized that a principal application of the technique would be to reduce Doppler shifts in freqwncy stand9tds. Loser cooling is still thought to be eaxntid to achieve uncertainty significantly smaller than 1 part in io"; however, a number of other problems must be solved to achieve this goal with stored atomic ions. For both RF/microwave and optical frequency standards based on trapped ions, some of theae problems are discussed. Laser cooling of trapped ions also appears to be important for other reasons in metrology. For example, for frequency standards, cooling to the zero-point of motion should enable the creation of quantum mechanically correlated statas for improved signal-to-noise ratio in spectroscopy, or provide accurate " e n t of Stark shifts. cooling to the zero-point of motion also enables the creation of nonclassical states of motion or correlated states which may be applicable to sensitive detection, quautum computation, or to test quantum " e n t principles. Techniques to achieve laser cooling to the zero-point of motion are briefly described.